NO PLAGIARISM DUE MONDAY SEPTEMBER 16,2019. ATTACHED ARE RESOURCES TO HELP WITH ASSIGNMENT

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1Forensic Science and Criminalistics

Associated Press

Learning Objectives After reading this chapter, you should be able to do the following:

▪ Define forensic science and how it contributes to a case, as well as explain the CSI Effect and the scientific method.

▪ Summarize the history of forensic science and contributors to the field. ▪ List and describe some forensic science specialties. ▪ Identify the elements of a forensic investigation, how physical evidence can be produced, and forensic analysis.

▪ Describe the work and work product of a forensic scientist. ▪ Describe the U.S. court system, and the key rulings on physical evidence admissibility through expert testimony.

▪ List and discuss major issues in forensic science today.

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Learning Outcomes After reading this chapter, you should be able to

▪ Describe firearms, projectiles, and cartridge casings and the role each plays in investigations. ▪ Describe proper collection and handling of firearms evidence. ▪ Explain firearms analysis and conclusions formed from the evidence. ▪ Describe gunshot residue and how it is analyzed. ▪ Identify tools, their marks, and how this evidence is collected and analyzed. ▪ Explain how documents are collected and analyzed.

Steve Helber/Associated Press

Pattern Evidence II: Firearms, Tool Marks, and

Documents Analysis

Introduction

Introduction This chapter continues the discussion of patterns for individualization. It will specifically cover firearms and tools used in cases involving forensic analysis and disputes that arise about the authenticity or author of a document in evidence. The major premises for these identifications are that no two guns make identical markings on bullets and cartridge cases and that no two people have identical handwriting.

Many of the analyses completed in these areas of forensic science depend on agreement of class characteristics, followed by individual characteristics, in that order. In Chapter 1.4 we defined class and individual characteristics. We talked about them again in Chapter 8.3. Let’s review these concepts briefly in the context of this chapter’s subjects. A class characteristic places several items in the same category because they are the same in some way. For exam- ple, if an examiner is analyzing a document to see if a suspect may have written it, analysis could be run on the ink on the paper. The results will connect the ink to a particular manufac- turer of pens. If the suspect owned or used that type of pen, he or she could be included—but so could anyone else who used that type of pen.

In firearms analysis, class characteristics are also very important because of their ability to narrow the focus of a case. Class characteristics in firearms cases are determined by the manufacturer. They can include the number and width of lands and grooves in the barrel of a gun, the direction of twist, and the caliber of the gun. The firearms analyst can quickly include or exclude a particular weapon as having fired a bullet through comparison of these manufactured characteristics. A cartridge is an unfired case containing a bullet. Once it has been fired in a weapon, it is a cartridge case, or cartridge casing. Cartridge casings can also be examined using class characteristics to identify the caliber and features of the weapon for which they are intended. There are center-fire and rim-fire cartridges, and cartridge cases from semiautomatic weapons will have extractor and/or ejector markings. (The exception to these analyses is shotgun ammunition, as will be discussed later). With firearms identifica- tion, individual characteristics are specific to a particular weapon.

Individual characteristics are random in nature. In documents analysis, the way a person writes is the product of years of development, to the point that the writer is unconscious of his or her handwriting. Unconscious writing has combinations of characteristics that can make it easily identified. In terms of individual characteristics for firearms, the machines used to put the grooves into the barrel of a gun change over time and impart microscopic striations to the barrel. These striations, seen within the rifling in a barrel, transfer to the surface of the bullet and can be compared to a known bullet fired from a particular gun. The same acciden- tal microscopic markings can be found on many tools, such as the tip of a screwdriver. All of these microscopic imperfections can be transferred to another surface and compared back to the tool that made them.

In summary, comparison of class characteristics allows examiners to narrow the focus to a set, or class, of items, while the individual characteristics will allow them to tell which, if any, item in the set left the markings behind. We will first look at the comparison and identifica- tion of firearms in forensic science. It should be noted here that the markings on bullets and cartridge cases from guns are a type of tool mark. That is, tool marks represent the broader general category. But non-firearm-related tool mark cases are less frequent in forensic case- work. (You could also think of bite marks, which we discussed in Chapter 8, as a type of tool mark, where human teeth are the tool.) A terminology note: Comparing bullets and cartridge

Section 9.1Firearms

cases with test fires from particular weapons to find the weapon that fired the questioned bullet is called firearms identification and is not equivalent to ballistics. Ballistics is the phys- ics of projectile flight through the air from barrel to target. Ballistics can come up in recon- structions involving fired weapons, but it is not the same thing as firearms identification.

There is one kind of trace evidence that we did not discuss in Chapters 6 and 7, because it is closely associated with firearms: gunshot residue. This topic will be included here.

9.1 Firearms Over the years, research and development in firearms has concentrated on increasing their range and accuracy. Propellants, the materials used to generate enough force to propel the bullet, were improved for range, but one of the most fortuitous developments involved rifling in the barrels of the firearms. The rifling in a barrel of a gun resembles the striping of a candy cane, a spiral of raised and lowered areas on the inner surface of the barrel of a firearm. Rifling, shown in Figure 9.1, imparts spin to the projectile. A projectile is defined as some- thing that can be propelled—in the case of firearms, a bullet. When a projectile is spinning, it is very similar to a top. While unstable and easily knocked over when not spinning, a top is very stable when spinning and tends to remain upright. This spin, when imparted to a fired projectile, will result in stability that increases accuracy over a longer range. Some firearms examiners have compared this to a quarterback throwing a football. If the football spirals, it will travel a greater distance with more accuracy than one thrown end over end. Rifle and pistol barrels are rifled. Shotgun barrels are not.

Figure 9.1: Rifling of a gun barrel

The barrel of a firearm has spiral cuts called rifling, which is made up of a series of lands and grooves. This allows the bullet to travel farther and with more accuracy.

Before the inclusion of rifling in the barrel of a firearm, a bullet comparison was accomplished by comparing the caliber of a projectile to a possible firearm manufacturer. The use of rifling in the barrels of firearms has not only improved accuracy and range, it has had the added benefit

Groove

Land

Section 9.1Firearms

of imparting macroscopic and microscopic markings onto the fired projectiles. The macro- scopic markings are easily seen with the naked eye and represent the lands and grooves in the barrel of the firearm. Lands are the raised portions of the barrel and are what remains of the original surface of the barrel before the grooves were formed. The grooves are the lowered spaces between the lands. These are some of the class characteristics that an examiner will use to determine if a particular class of weapon is involved in a case. The microscopic mark- ings represent the individual characteristics the examiner will use to determine if a particular weapon in the class fired the projectile. These are also known as striations on the bullet.

Striations found in a gun barrel result in individualized patterns that may be unique among the members of their class and can be found on the fired projectile. If all class characteristics are the same, the analyst can compare the striations. If sufficient information matches between the evidence and a known standard generated by the analyst, he or she can say the two items came from the same gun. There are several other conclusions that can be reached by the ana- lyst. If class characteristics do not match between a bullet fired from a suspect’s weapon and the evidence bullet, the analyst can exclude the item, since individual characteristics cannot match if class characteristics do not match. If class characteristics match between the stan- dard and evidence but there is not enough information to form a definite link between the evidence and standard, the analyst can call the results inconclusive. This type of analysis has been accepted in the courts since the early 1900s (National Institute of Justice, n.d.).

The idea of this type of analysis might be hard to visualize. How did those markings get into the barrel of the gun or, in the case of cartridge cases, onto the firing pin and breech face (the back end of the barrel of the gun, which helps contain the explosive forces released upon fir- ing)? How are they individualized? These things relate to the manufacture of the firearm itself.

The rifling in the barrel of a firearm is produced by one of three main methods—the broach- cutting, button, and mandrel methods. In the broach-cutting method, blades are used to shave metal from the inside of a metal tube, which will become the barrel of a firearm. These shaved areas become the grooves in the barrel of the firearm. The unshaved interior surfaces of the tube that remain become the lands of the barrel. Each time the blades are used, microscopic imperfections on the blades change with use. These microscopic imperfections leave mark- ings that are impressed into a projectile as it travels down the barrel of the firearm.

The button method involves the use of a metal plug, formed to represent the negative of what will be the final configuration of the inside of the gun barrel. The barrel is formed by pushing or pulling the button through the length of the metal tube that will become the barrel in a spi- ral motion, pressing the grooves into the tube. Due to the pressures involved, the compressing surface of the button changes at the microscopic level and leaves different microscopic imper- fections along the grooves of each barrel created.

The last method of forming a barrel for a firearm uses a mandrel, or rod, that has been formed to be a negative of the gun barrel. This rod is inserted into the tube that will be the gun bar- rel. Hammers compress the tube around the rod. When complete, the mandrel is twisted out of the newly formed barrel. Again, pressures exert stress on the barrel and the rod. The rod changes with each use at the microscopic level and leaves imperfections on the inside of the gun barrel that will be transferred to bullets that are fired through the firearm. The imperfec- tions that each rifling method produces are what can be used to individualize a firearm.

There is another point of terminology worth mentioning here. When a firearms, tool mark, or questioned document examiner says “identification,” he or she means “individualization.”

Section 9.1Firearms

Two old cases were exceptionally instrumental in the development of the firearms identifica- tion field in the United States: The Sacco and Vanzetti case in Massachusetts and the St. Valen- tine’s Day massacre in Chicago.

Case Illustration: State of Massachusetts v. Sacco and Vanzetti On April 15, 1920, there was a daring robbery of a cash payroll in South Braintree, Massachusetts. In those days, factory employees were paid in cash. Two men were killed as they were transporting payroll cash to the factory at the time of the robbery. Police atten- tion focused on Nicola Sacco and Bartolomeo Vanzetti, not only for the Braintree robbery but also for another earlier holdup. The getaway car may have been the same one in both cases. When arrested, Sacco had a .32 Colt semiautomatic pistol. Test firings and compari- sons matched that gun to a bullet taken from the body of Berardelli, one of the murdered payroll guards. A firearms examiner from the Massachusetts State Police testified at the trial. In 1921 both defendants were convicted of murder and sentenced to death. The fire- arms evidence was the only forensic evidence in the case, and firearms identification was in its infancy at the time. After voluminous postconviction legal proceedings, both men were executed in 1927.

Sacco and Vanzetti were anarchists; they believed that the government should be over- thrown by violent means, if necessary—a fact that did not help their case. There have been several reexaminations of the bullet evidence, and it has always been verified that the questioned bullet from Berardelli’s body was fired by the .32 Colt handgun. However, allega- tions of tampering with the bullets and the gun have arisen over the years, and the chain of custody is not very accurate or verifiable. Many people believe that Sacco and Vanzetti were arrested, convicted, and executed mainly because they were anarchists and that this case was in fact a miscarriage of justice. This provides a classic example of how chain of cus- tody needs to be solid in any forensic case, especially in a capital case, which often involves firearms.

Reflect On It The firearms evidence was the only forensic evidence in this case, although the chain of cus- tody cannot be verified. Due to this, do you think the verdict would be the same today? Why or why not?

Case Illustration: State of Illinois v. Capone The St. Valentine’s Day massacre occurred on February 14, 1929, at a garage at 2122 N. Clark Street in Chicago. This crime was gang related, and the well-known gangster Al Capone was behind the murders. Five members of a rival gang were lined up against the wall of a garage and massacred using Thompson submachine guns. The perpetrators were dressed in Chicago Police uniforms, which is how they lured the victims into the location. Police were eventually able to solve the case and tie it to the Capone gang. Bullets and cartridge cases were collected from the scene, along with the weapons, and were examined by Colonel Calvin Goddard. He was able to associate the machine guns with the fired evidence.

After years of tolerating violent gang activity in Chicago, the public had had enough with the Chicago mob and their violence. Gang activity declined in the city. Goddard’s involvement in this case led to the formation of a firearms identification laboratory at Northwestern

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Section 9.1Firearms

Types of Firearms There are several major types of firearms that are seen in forensic laboratories. These include different types of handguns and long guns. Handguns, commonly called pistols, are catego- rized into two major types. The first uses a cylinder with several chambers containing the cartridges. This is termed a revolver and is perhaps best represented by the six-shooter. The second type of handgun uses a magazine to hold the cartridges. This magazine is usually contained within the grip of the handgun. This type of weapon is usually termed a semiau- tomatic firearm (pistol) and can be represented by the .45 caliber Colt. Figures 9.2 and 9.3 provide examples of a revolver, a pistol, and their parts.

Figure 9.2: Revolver

A revolver handgun has a cylinder that holds the cartridges. After a cartridge is fired, the cartridge casing stays in the chamber, and the hammer can be pulled back to rotate the cylinder and place another cartridge under the firing pin.

Adapted from “Chapter 2—Firearms and Ammunition,” by Texas Parks & Wildlife, n.d., Retrieved from https://tpwd.texas.gov/ education/hunter-education/online-course/firearms-and-ammunition-1.

Case Illustration: State of Illinois v. Capone (continued) University, which was later transferred to the City of Chicago as its forensic lab. Goddard is considered a founding father of forensic firearms identification in the United States.

Reflect On It Thompson submachine guns can fire a number of bullets in seconds. If you were the exam- iner for the St. Valentine’s Day massacre case, how would you go about analyzing all the fire- arms evidence?

Think About It

There was a backlog of firearms evidence in public labs in the United States as of 2014. Compared with other types of evidence, such as drugs and DNA evidence, the backlog is smaller. Why do you think this is the case? Can you think of some ways to reduce the back- logs in firearms examination?

Chambers

Trigger

Cylinder

Hammer

Section 9.1Firearms

Figure 9.3: Semiautomatic pistol

A semiautomatic handgun has a magazine that holds the cartridges. When fired, the slide moves backward, and the cartridge casing leaves through the ejection port. As the slide moves forward, it picks up another cartridge from the magazine and loads it into the chamber.

Adapted from “Chapter 2—Firearms and Ammunition,” by Texas Parks & Wildlife, n.d., Retrieved from https://tpwd.texas.gov /education/hunter-education/online-course/firearms-and-ammunition-1.

There are some differences in the operation of these firearms and the evidence left behind from their use. The revolver operates when the hammer of the firearm is pulled back. This rotates the cylinder one position. A live cartridge is now under the firing pin. When the shooter pulls the trigger, the hammer strikes the firing pin, setting off the cartridge. The bul- let travels down the barrel of the gun, propelled by the expanding hot gases from the burning of the propellant. In order to fire the gun again, the hammer must be pulled back to rotate the cylinder so a new cartridge is in firing position.

There are two types of revolvers. The first, called a single-action revolver, requires manual cocking of the hammer. In other words, the shooter must pull the hammer back to ready the firearm to fire. The double-action revolver allows the shooter to pull the trigger, which simultaneously cocks the hammer, rotates the cylinder, and fires the weapon with one pull. This increases the rate of fire of the pistols. A disadvantage to this type of weapon for forensic work is that unless the shooter has to reload the weapon, cartridge casings will not be left at a crime scene.

SlideSlide

MagazineMagazine

Grip

Muzzle Muzzle

Trigger

Section 9.1Firearms

Semiautomatic pistols were developed in the early 1900s. As mentioned, the cartridges are stored in a magazine in the grip of the pistol. When a shooter readies this type of weapon, he or she will pull back the slide, which is located at the top of the frame of the pistol, and release it. As the slide moves forward, it picks up the cartridge at the top of the magazine and slides it into the firing chamber. At this point, the hammer is placed in the firing position. When the shooter pulls the trigger, the hammer strikes the firing pin, setting off the cartridge. The bul- let travels down the barrel of the gun, propelled by the expanding hot gases from the burning of the propellant. At this time, a second action is taking place, the opposite and equal action to propelling the bullet down the barrel of the gun. Remember, the hot gases try to expand in all directions. The firing chamber prevents them from expanding to the sides. Since the slide of the gun is movable, while the bullet is being forced through the barrel, equal and opposite action will force the slide backward. As the slide goes back, the just-fired cartridge casing is ejected from the firearm through the ejection port, and the hammer is cocked. The slide reaches its farthest distance back, comes forward, picks up another cartridge at the top of the magazine and slides it into the firing chamber. The pistol is again ready to fire. When the shooter pulls the trigger, the process repeats.

Semiautomatic weapons require that the trigger is pulled each time the weapon fires. Maga- zines typically hold 8 to 15 cartridges, though some have been designed to hold more. This type of weapon offers a benefit to investigators. Cartridge casings are ejected from the weapon each time it is fired. This evidence can be collected and submitted to the firearms examiner so that even if fired bullets are not found, evidence exists that can help determine the gun used in a crime.

Automatic firearms are weapons that are designed to fire as long as the trigger is held down. These weapons are usually of the true assault weapon variety—or larger—such as machine guns. They are illegal in the United States except under special permits from the BATF, although some people hold these weapons illegally. At crime scenes, they will leave behind the same projectiles and cartridge cases as semiautomatic weapons.

Long guns are designed to be fired using the shoulder for support. There are two main types of long guns seen by investigators: rifles and shotguns. The main difference is that shotguns do not have rifling in the barrel. This means that fired projectiles from a shotgun cannot be compared to test fires from a particular weapon. Ammunition for a shotgun is a shotshell. It usually contains buckshot but can contain a single projectile known as a slug. Once fired, it is a shotshell case or casing. Rifles, on the other hand, have rifling in the barrel, and their projectiles can be used for comparison. The function of these weapons is very similar to that of the handguns. Rifles and pistols are characterized by the diameter of their barrels. In rifled barrels, the diameter is measured land-to-land. This feature is called caliber. Caliber can be stated in inches or millimeters. It is sometimes stated in what might be called firearms slang. For example, a .380 semiautomatic pistol has a barrel diameter of 0.38 inches. But, a so-called .38 special has a barrel diameter of 0.357 inches, the same as a .357 magnum. Caliber is a class characteristic that can also help in identifying a type of firearm.

Types of Projectiles There have been many types of projectiles designed for use in weapons. Among the first were the simple round balls made of lead used in guns before barrel rifling. After rifling was added, bullets were elongated to facilitate use of the rifling to pick up spin. After this, many different

Section 9.1Firearms

designs of bullets were used. The designs often reflected their use. Adaptations to the early round lead bullets included flattening the end of the bullet rather than rounding it. This allowed the diameter of the bullet to expand more after it hit the target, doing more damage. After a while, the end of the bullet was hollowed out, forming the hollow-point bullet that was supposed to expand further upon contact with the target. Then metal coverings were added to the projectile. This would limit deformation of the projectile after it struck, allowing more penetration into the target. The effect of design changes of the projectiles was to inflict more damage to the target.

Forensic examiners and law enforcement are not typically concerned with these changes other than how they affect the characteristics of the bullet when it fires. Less deformation will result in a greater chance of a successful comparison between two projectiles. More deforma- tion or actual destruction of the projectile will mean less information available to the exam- iner, precluding comparisons or identifications. An example of this is exploding-tip bullets. This bullet type is hollowed out, and a small explosive charge is placed in the cavity. A small ball bearing is placed in the cavity as well, and the cavity is then sealed. The theory is that when the bullet strikes the target, the ball bearing will be forced into the explosive, causing the bullet to rupture. This will fragment the bullet into pieces small enough that comparisons may not be possible.

Today, instead of lead as the main component of the projectile, metal alloys are used. Some are harder than lead and result in less deformation. Others are frangible, which means they will break apart when they strike their target. In any event, the investigator must be aware of the possible evidence to be found at crime scenes and be prepared for anything from a pristine bullet taken from a wall to fragments taken from a body.

Cartridge Casings In situations in which fired projectiles may not be found, cartridge casings may be very valu- able. If a cartridge casing is collected, it can provide the investigator with some immediate information that will also be important to the firearms examiner. On the back end of the car- tridge casing are markings placed by the manufacturer; these are called the headstamp. The headstamp includes information such as the caliber of the cartridge and the manufacturer. Additionally, the breech face markings from the firearm itself, which may be found on the cartridge casing, can be used to tie it to a particular gun just as easily as a fired projectile. The breech face is essentially the back end of the firing chamber of a firearm. The cartridge case will be forced backward as the bullet is forced out of the barrel by the burning propellant. Breech face markings are marks left on the breech face from the recoil of the firearm. The firearms examiner can make use of several different markings that may be present, such as

Think About It

Which bullet design for a 9 mm semiautomatic pistol do you think would be easier for a firearms examiner to use in comparison after the bullet has been fired and has hit a hard surface: a copper-jacketed hollow point, or a simple, lead f lat-nose bullet? Why?

Section 9.2Collection and Preservation of Firearms Evidence

extractor and ejector markings, but usu- ally the breech face and firing pin mark- ings are sufficient, since they will provide the individualizing characteristics neces- sary to identify the cartridge case to the suspected firearm.

When the cartridge is detonated, the firing pin strikes the primer. This will leave the impression of the firing pin on the primer. The propellant is detonated and the pro- jectile forced down the barrel of the gun because of the hot expanding gases. At the same time, due to equal and oppo- site actions, the cartridge casing is forced backward into the breechblock. Markings, both microscopic and macroscopic, are impressed onto the back of the cartridge. Again, since these are machined parts, they are individual. Studies have been done to determine the individuality of these markings and their potential for use in casework (Smith, 2005). Bullets, cartridge cases, and shotshell cases are all known as fired evidence.

9.2 Collection and Preservation of Firearms Evidence The evidence, whether it is a bullet, cartridge casing, or gun, needs special care. The fired projectiles and cartridge casings need to be protected from damage and change. In order to do this, the investigator must remember that anytime metal strikes—or even rubs against— metal, marks can be left behind. If all of the cartridge casings collected from a crime scene are placed in the same box or bag with no other protection, those casings will rub together, caus- ing additional marks. Any damage caused by this contact can lower the chances of an exam- iner making an identification. It is the same for the fired projectiles. If placed unprotected in the same package, damage will result.

Several methods of packaging are available. Small coin or jewelry boxes can be used to store individual items. Multiple items can be stored together, as well, if they are individually wrapped in cotton or tissue. The main rule is that metal should not touch metal. In addition, these items cannot be labeled or marked directly. The best method is to package them each in their own individual containers with appropriate numbering and labeling on each package.

Firearms packaging has two goals: protect the personnel handling the evidence and pro- tect the firearm from damage. Firearms seized at a crime scene have a good chance of being loaded, which makes them very dangerous. The best thing to do, for everyone’s safety, is to unload the gun before packaging. This should not be taken lightly. Ideally, the investigator should include enough information that the examiner can return the firearm to the same con- dition it was in when found at the crime scene. Cartridges and cylinders of revolvers can be marked so the proper cartridges can be reinserted into their chambers and the proper cham- ber placed under the hammer. The investigator should also note the position of the hammer

Brennan Linsley/Associated Press Cartridge casings can be helpful evidence, and like analyzing projectiles, a lot can be gleaned through comparison. Do you think casings are less valuable than bullets themselves as forensic evidence?

Section 9.2Collection and Preservation of Firearms Evidence

in the report of the crime scene. Was it cocked or down? Was the safety on or off ? Was the cartridge under the hammer live, or had it been fired? All of these bits of information may be important later in the investigation.

In a semiautomatic pistol, the magazine can be removed and the cartridge in the chamber removed and packaged sepa- rately. The investigator should take care to note everything about the weapon related to hammer position, safety position, whether a live cartridge was in the firing chamber, whether there was something like a casing jamming the ejector mecha- nism, and any other details about the gun that could become important to the inves- tigation. From the investigator’s notes, the examiner should then be able to place all compo- nents back in the gun as they were found at the crime scene. Care should also be taken with victim and suspect statements about any type of firearm. If, for instance, the suspect said the weapon had the safety on, safety position should be noted, but this statement should also be reported to the examiner (who can check to see if the safety was broken). Similarly, if the sus- pect indicates that the gun went off when hardly any pressure had been placed on the trigger, the examiner can check the trigger to see if it had a very low pull weight. Everything should be noted and given to the lab.

Care should be taken to prevent stray fingerprints from getting on the evidence, especially if fingerprints are important to see who used the firearm. Therefore, gloves should be worn. Boxes are available in which the firearm can be packaged along with various other pieces of evidence so that nothing will be damaged on its way to the lab.

If a firearm is found in water, the best method of submission to the laboratory is to place the firearm in a container of the same water it was found in. The water should cushion the gun to prevent it from firing so that the gun does not need to be unloaded. Packaging in the same water will prevent chemical action should there be different reactive chemicals present. In the laboratory, the examiner will treat the weapon with clean water and wash it with solvents. He or she will then oil and reassemble it to prevent oxidation or rust, which can destroy infor- mation present in striations in the rifling or on the breechblock.

In any event, packaging for safety is important. It is a common mistake to not completely render a firearm safe by making sure it is unloaded before sending it to the laboratory. Once the evidence reaches the laboratory, a firearms examiner should immediately take charge of it. Additionally, for those agencies sending firearms evidence through the mail, it is very important to make sure the firearm is unloaded, because it is illegal to mail loaded weapons.

Once evidence has been received into the firearms section, there are several types of analyses that can take place. Some analyses are dependent on the requirements of the agency and the nature of the crime, while others are limited by the evidence submitted.

dyscoh/iStock/Thinkstock Firearms evidence is best packaged separately so as not to compromise anything. Do you think the chain of custody with firearms evidence is more complicated than with other evidence?

Section 9.3Analysis of Firearms

9.3 Analysis of Firearms There are several databases that assist forensic firearms examiners in their work. Currently in the United States, the system is the National Integrated Ballistic Information Network (NIBIN). This system utilizes the Integrated Ballistics Identification System (IBIS). NIBIN assists the examiner in comparing a fired projectile or cartridge casing to those from other crimes. A system called Matchpoint+ is used in conjunction with NIBIN, which allows the examiner to perform examinations and comparisons of stored microscopic images of fired projectiles and cartridge casings to those from newer crime scenes.

Another system that aids the examiner is the FBI general rifling characteristics (GRC) system. This allows the examiner to input class characteristics of recovered fired projectiles —such as the caliber, number of lands and grooves, and direction of twist—and obtain a list of potential manufacturers and models of firearms that could have fired the recovered projectiles.

Analysts do not use these systems to make a match for them. The database can provide possible relationships between stored images and the projectile being examined, but the examiner makes the final determination only after direct comparison of the evidence to a known standard projectile that has been fired from the suspected weapon. Computerized searches are helpful in associating cases whose connections would not otherwise be obvi- ous. A cartridge case recovered at a shooting scene in Chicago might match a case recovered from another scene in Detroit, for example. This shows that the same gun was probably used, even though the gun itself has not been recovered. There are several types of firearms analysis that can be done.

Since the late 2010s, advances in technology have allowed for the 3-D printing of firearms. Among many unique features, 3-D firearms lack serial numbers, making them much more dif- ficult to trace. There is still debate regarding whether or not the blueprints for these weapons should be allowed to circulate freely on the Internet, but there is no doubt that they will cause new challenges for forensic investigators.

Analysis and Comparison When a firearms analyst is presented with a fired projectile, it may appear that there is little to do when this is the only evidence. However, the analyst can provide information that can help investigators. Looking at the projectile, the analyst can classify it according to its class characteristics, the number of lands and grooves and their direction of twist, the measure- ments of the widths of the lands and grooves, and the caliber. Because these are class char- acteristics, the manufacturer decides what they will be. Some may decide to have land and groove widths equal around the circumference of the barrel, while others may want wider grooves with narrow lands. This means that when the analyst has determined the exact char- acteristics of the unknown projectile, those characteristics can be entered into the FBI GRC database, which can determine the manufacturers’ models of weapons that fit. The list could be short, but in some cases in which characteristics are common, it could include many types of weapons. Upon getting this list, the analyst can inform law enforcement of possible weap- ons that could have been used in the crime.

Section 9.3Analysis of Firearms

The firearms examiner can also place the projectile on a microscope that is attached to a computer and, by rotating a scanner along the length of the bullet, can scan the projectile into the NIBIN system or search the NIBIN database. It is possible that the weapon was used in a previous crime in which another projectile was recovered. If an apparent match is found through computer comparison of the striations on the stored images, the examiner should look at the projectiles directly to see if they could have originated from the same weapon. If so, the examiner can inform the agency that two crimes were committed with the same gun. If there is no apparent match, the unknown projectile will remain in the database in the event some future projectile is recovered in another crime.

If the examiner receives a cartridge case, the case can be scanned into NIBIN and searched. There is no file for cartridge cases like the GRC file for bullets. Remember, however, that the class characteristics found on cartridge cases are mainly the caliber and the shape of the fir- ing pin, so even if there were a database, the resulting suspect weapon list would be cumber- some. Should there be a possible matching cartridge case in NIBIN, the examiner will directly compare the cases for a possible match to tie crimes together. Or, if there is no possible match, the casing information will remain in NIBIN for future comparisons.

Ideally, the examiner would like to receive a weapon with a fired projectile or cartridge case evidence. When this occurs, the examiner will test fire the weapon and collect the fired evi- dence. Today weapons are fired into water tanks, and the projectiles are recovered before the next test fire (as shown in the cover photo for this chapter). In order to test the reproduc- tion of information from the suspect firearm to the fired projectiles, the examiner will collect multiple test-fired examples. First, the examiner will compare the test-fired projectiles and casings with each other, using a comparison microscope. We mentioned this type of micro- scope before, in Chapter 6. It has two objective lenses bridged to one set of ocular lenses. This allows the examiner to compare the test-fired exhibit to the evidence side by side, looking at them simultaneously.

At this point, the examiner compares the individual characteristics present in the fired evi- dence. On fired projectiles, these are the striations located in the lands and grooves, while on the cartridge cases they are the striations left behind by the firing pin and the breechblock.

After comparison of the test-fired evidence, the examiner will compare test-fired evidence to case exhibits. It is unlikely that every striation will match between test-fired projectiles or cartridge cases, or between the test-fired exhibits and the evidence exhibits, because each bullet makes slightly different contact as it travels down the barrel of the gun. However, ana- lysts have been trained to determine when two projectiles or cartridge cases originated from the same firearm by looking at the striations, which is known as pattern matching. Some

Think About It

Why do you think the examiner first wants to compare the known test-fired evidence with itself before comparing it to any questioned evidence?

Section 9.4Gunshot Residue

work has been done to make this process more quantitative through the use of the consecu- tive matching striation approach. This is a method whereby the examiner counts a number of striations on the bullet and then must have a minimum number of striations in a row that match. The Association of Firearms and Tool Mark Examiners (AFTE) is the guiding body for these experts. Its guide for examiners establishes protocols to be followed when determin- ing if two bullet markings match. It encourages examiners to utilize their skills in determin- ing if there is sufficient agreement between the test-fired exhibit and the evidence exhibit to determine if the two came from the same weapon (National Institute of Justice, n.d.) There is also a firearms and tool marks subcommittee in the OSAC structure that was described in Chapter 1. But no firearms or tool mark standards have yet been adopted. Using his or her knowledge, training, and experience, the examiner will reach a conclusion about the tested evidence. After reaching this conclusion, it will be reported to the agency that submitted the evidence to the laboratory, and eventually the examiner may present these findings in court.

Upon the conclusion of their analysis, examiners will report their results. If there was agree- ment between the class and individual characteristics greater than between any two differ- ent firearms, an examiner can say the test-fired exhibits and submitted evidence came from the same firearm—this is an identification. If there was agreement between all of the class characteristics, and agreement with the individual characteristics, but there was damage to the evidence or insufficient individual characteristics to prove a match, an examiner can make a determination of inconclusive. If the examiner finds disagreement in class and indi- vidual characteristics, he or she can eliminate the item as coming from the same weapon— this is an exclusion. Lastly, if the submitted evidence is lacking in microscopic markings or has been badly damaged, mutilated, or fragmented, the examiner can conclude that the evidence is unsuitable for analysis (National Institute of Justice, n.d.; Bunch, Smith, Giroux, & Murphy, 2009).

To help examiners validate their methods and conclusions, studies have been done using sequentially manufactured barrels to determine whether individuality could still be dis- cerned. One such study was completed by Murdock in 1981 (see also Brundage, 1998; Miller, 2000; Murdoch, 2011). These studies, as well as others, reveal that in every instance, the bul- lets could be distinguished. Consecutively manufactured barrels should have the most similar individualizing marks. If they can be distinguished, the thinking goes, then so should every other barrel, even of the same make and caliber. Though some challenges have been brought in the courts regarding the efficacy of the information related by firearms examiners, this analysis is still widely accepted in the courts today.

9.4 Gunshot Residue When a gun is fired, residue is forced down the barrel and out the muzzle of the gun. This gunshot residue consists of particles formed from smoke, dirt, gunpowder, bullet residue, and primer explosive components. Some of this residue is also forced out of the sides of the chamber. Especially with many handguns, some of this residue will be deposited on the hand holding the gun. Residue can go out of the barrel, but it doesn’t travel very far because the particles are small.

Gunshot residue cannot prove that someone fired a weapon. It only shows that the person’s hand was in the vicinity of a fired weapon. Suppose a woman is found shot dead in her bed,

Section 9.4Gunshot Residue

and her husband is the obvious suspect. He might have gunshot residue on his hand, but so might she. The hands could have been near the weapon when it fired and acquired some resi- due. The husband might claim the death was an accident or that she shot herself and he was trying to stop her. It is unlikely that gunshot residue testing will help sort out the alternatives. On the other hand, suppose a person is found alone in a car in a deserted area with a single gunshot wound to the head. The gun is in the car. The bullet from the body matches the gun. And suppose there is gunshot residue on one hand and not the other, and that it corresponds to the hand the person would have used to hold the gun. This finding corroborates, but does not by itself prove, that this case was a suicide. In other words, analysis of gunshot residue on the hands of people at crime scenes may not help the case, and in some cases it may confuse the issues of the investigation. Very few agencies actually complete this type of analysis in the labs today. However, there are cases in which analysis might help.

Analysis and Comparison Gunshot residue is identified by its elemental composition or a combination of its elemental composition and particle structure. Today gunshot residue is collected by using a kit that is specifically for gunshot residue and contains metal studs with sticky tape on top for the resi- due to adhere to. After collection, instrumental analysis will be performed to look for the com- ponents of gunshot residue. In the past, forensic labs used atomic absorption spectrometry, which can tell which elements are present in a sample in order to identify which specimens to test for gunshot residue. This test looked for antimony and barium, both components of the primer explosive, and lead, which can be a component of the primer or the core of the bullet. The presence of these elements alone was considered indicative of, but not proof of, gunshot residue. Now many forensic labs have acquired scanning electron microscopes; these have been used for gunshot residue identification. These microscopes are very powerful, enabling the analyst to see the particles of gunshot residue. With an attachment called an energy-dis- persive X-ray spectrometer, the elemental composition of the particles can be determined.

Another application of gunshot residue is in reconstruction. Reconstructing the scene can help determine the distance from the firearm muzzle to the target. Gunshot wounds that are point blank or extremely close leave distinctive patterns on the body. But at distances between a few inches and a few feet, there may still be gunshot residue patterns on the body or the clothing. This pattern can be used to estimate how far away the gun was from the target. There is no formula, so it has to be done experimentally. The same firearm and ammunition is used to fire shots at measured distances from a clean, white target. The gunshot residue pat- terns are then compared with the pattern seen in the case to provide a distance estimate. Since gunshot residue doesn’t travel very far, at a certain distance there won’t be any pattern since the residue all falls to the ground before reaching the target.

Think About It

If a suspect in a case indicates that he or she and the victim of a shooting were struggling over a gun and the gunshot residue pattern indicates the victim was at least 3 feet from the barrel of the gun, what can be said about the suspect’s alibi? Explain your reasoning.

Section 9.5Tool Marks

9.5 Tool Marks Tool mark analyses are a subset of the analyses performed by firearms and tool marks exam- iners. As with firearms, a hard object or tool is brought into contact with a softer object and leaves a mark. Since tools, such as screwdrivers and crowbars, are machined objects, they will have individual characteristics from the manufacturing process that can be tied to markings left behind when the tool was used. Tools can be manufactured in various ways, but some of the most common involve cutting, in which metal is removed from an object in order to shape it into a tool. Here, a very hard apparatus is used to chip, cut, or drill small pieces from the original block of metal in order to shape it into a usable tool. Other tools can be formed with the use of extreme heat and/or pressure to form the metal into the desired shape. Often this also involves forging, hammering, or squeezing the metal into the desired shape. The end result of these processes is a tool that has class characteristics determined by the manufac- turer and individual characteristics determined randomly in its creation.

Tool marks are found in burglaries, accidents, vandalism, and other cases. It is the job of the examiner to determine if evidence tool marks submitted by the law enforcement agency were made by a tool that, ideally, was submitted as well. The examinations are very similar to those in firearms evaluation. The examiner will make test marks using the suspect tool and com- pare them, first between test markings and then between test mark and evidence tool mark.

This sounds easier than it is. Consider that a bullet can only pass through the barrel of a gun in one direction. A tool can be used in many different ways. Each different mode of use will alter the shape and appearance of the tool mark. In this case the examiner must determine the way the tool was used to duplicate the evidence mark. If the mark can be duplicated and the examiner can conclude that the suspect tool made the evidence mark, then the agency could solve the crime.

There are many different tools in use, but they can be narrowed into several classes of tools, often recognizable by the marks they make.

Types of Tools and Their Marks Many types of tools are classified by the actions they have on items. For instance, a tool can be used to scrape a surface. This could be something as simple as removing paint with a flat- bladed scraper. However, screwdrivers, pry bars, or any other flat tool could also be used to scrape a surface. The markings will be impressed into the surface of the object that was scraped; ideally, the impressions will include microscopic characteristics that can be com- pared to a suspect tool.

Bolt cutters exhibit an action called pinching. The blades of the bolt cutters are aligned directly across from one another. When brought together against, for instance, a piece of wire, they pinch the wire, and when the blades close, the wire is severed. This differs from tools that are said to shear objects. Shearing tools have offset blades, so they do not directly close on one another but instead slide past one another, like scissors. If used to cut wire or plastic, it is pos- sible that markings from one or both blades will be left behind on the cut surface.

Section 9.5Tool Marks

Use of knives, axes, or other sharp, single- bladed tools will result in a slicing action. Again, marks can be left on the surface of the object being cut. The examiner will need to observe both sides of the cutting implement to determine its use in the crime. Marks of this type can be found in slashed tires and cut wires. Despite what is sometimes seen on various crime dra- mas, these types of marks are rarely able to be compared to marks on bodies of murder victims, because of the elasticity of the skin.

Wrenches can be used to force open a door- knob. Vices can be used to hold an object. These gripping tools are formed with two surfaces that can be forced together with an object in between. The held object can then be manipulated, but during this pro- cess, marks from the gripping surfaces can be left behind. These markings can be compared to a questioned tool.

Most people are familiar with prying types of tools. These can include pry bars, screw- drivers, and any other flat tool that can be inserted between two surfaces to separate them with the use of force. Their marks can be found in many places. Doors or windows that were pried open are com- mon examples. Crime scene investigators must remember that there are two sides to every tool and must examine the sur- faces with the marks very carefully to make sure they collect all information that may be present.

Tool marks have the potential to be found at many different crime scenes. Unfortunately, they are sometimes difficult to collect. Fortunately, there are ways to avoid bringing an entire door (for example) into the crime laboratory.

Think About It

Can you think of any other types of tools that can be used to commit a crime? What types of marks could they leave at a crime scene? Where might they be found at the scene?

Reed Saxon/Associated Press Tool marks can be made from a variety of objects. Can you think of any obscure examples of items that could leave tool marks at a crime scene?

Section 9.5Tool Marks

Collection and Preservation Tools are often used to gain entry at a burglary. Upon arrival at a burglary scene, the investiga- tor will try to locate a point of entry. With luck, there will also be a clue to the means used to gain entrance. The investigator may find that there are marks on the strike plate or lock on a door. Or perhaps there are marks left by a crowbar when it was forced between the door and the frame. In either case, how can investigators get the evidence to the laboratory?

The first example could be easy. The investigator could remove the strike plate or lock and carefully package it for delivery to the laboratory. The door is another matter. While it may be possible to remove the door and frame, it is not practical. Fortunately, there are modern casting materials available that are composed of particles so small they can penetrate the microscopic striations of the tool mark and capture the characteristics left behind by the tool. In the laboratory, the examiner can compare any evidence that is submitted, but if it is awk- ward or cumbersome, the analysis may be adversely affected due to the size of the item and the availability of instrumentation necessary to magnify the mark. Microcasting materials are easily obtained from many law enforcement supply houses or from forensic supply compa- nies, which are gaining popularity. These materials are easy to use, provide quality evidence, and alleviate the need to remove the victim’s door and frame from the house.

Care should be taken in packaging multiple items of evidence. As with firearms evidence, each piece of evidence is best packaged separately. This is true especially for tool mark evidence. Placing all of the items that have tool marks on them in the same box and submitting them to the lab can lead to disaster. If you recall with firearms evidence, bullets and cartridge casings can rub against one another, ruining the markings. The same holds true for tool marks. They must be kept away from one another in order to preserve them.

Tool marks without tools are relatively useless as evidence. Tools are needed for comparisons to be made because a suspect tool is necessary to make a mark that can be compared to the evidence mark. Care must be taken with any tools that are collected. All tools taken from a suspect should be individually packaged and labeled. Remember the chain of custody for all of these items as well.

Analysis and Comparison If evidence is carefully collected, individually packaged, and successfully delivered to the lab- oratory, will successful comparisons always come back from the examiner? Due to the diffi- culties with this type of evidence, the answer is no. The examiners will conduct the analysis of

Think About It

You are the primary investigator on a home burglary case. You find several points of entry, but you find tool marks on a back door and a window frame. How would you collect these tool marks as possible evidence?

Section 9.5Tool Marks

tool marks in the same manner as they do firearms evidence, by making a test mark with the suspect tool and then using the comparison microscope to compare that mark to the evidence mark. After compar- ison, the examiner will come to a conclu- sion, as she or he would do with firearms evidence.

Remember that bullets can only travel in one direction down the barrel of a gun. Analysis of fired evidence is simplified by that fact. On the other hand, tools can be used in an endless number of ways. The tool could have been used to pry at any angle from shallow to steep. It could have been used obliquely rather than straight on, and from either the right or the left. Different pressures on the tool will have effects on the clarity of the mark. Repeated use of the tool in a limited area can leave overlapping marks. All of these factors can result in unclear marks. There are surfaces that may not show tool marks well, such as a metal that could be harder than the tool or textured surfaces. The examiner must take all the possibilities into account when preparing the known marks from the tool. Known marks made in the labora- tory can then be compared with the questioned mark.

The conclusions that can be reached by examiners of tool mark evidence are identical to those from fired evidence analysis. Remember, they can say the evidence mark was left by the sus- pect tool if the class characteristics are the same and there is sufficient agreement between the individual characteristics. They can give an inconclusive result if class characteristics are the same but there is not sufficient agreement between the test mark and the evidence mark. They can say the tool did not make the mark if the class and individual characteristics differ. They can also say that the mark is unsuitable for comparison if there are insufficient charac- teristics left behind.

Now we will move to a different type of pattern seen in forensic casework. Here, the markings left behind are not compared to a tool but to the person who made the markings; this is hand- writing analysis. It can be found in a number of different types of forensic casework, but the comparisons will generally be used to determine the author or the authenticity of the writing.

Think About It

If a prying tool is used on a door, do you think you will get a better mark from the wood frame or the metal strike plate? Which will the examiner have the best chance of compar- ing in the laboratory? Why?

Jochen Tack/imageBROKER/SuperStock The ability to make test marks is important so that analysts have a known to compare their unknowns to. Do you think tool mark comparison can ever be absolute?

Section 9.6Document Analysis

9.6 Document Analysis Albert S. Osborn’s book Questioned Documents was published in 1910. Since that time, ques- tioned document examiners have been called on to determine the authenticity of documents and to confirm if the person who allegedly wrote a document really did so. The comparison of handwriting has been met with challenges in the modern courts, which seek to eliminate what is considered subjectivity for the more tangible objectivity of statistical analysis.

Today questioned document examiners are engaged in forensic work in four major areas as set forth by the Scientific Working Group for Forensic Document Examination (SWGDOC). The document examiner will complete analyses to reveal authenticity of a document by determin- ing whether it has been altered through additions or deletions. Document examiners also confirm or eliminate a suspect as a source of handwriting on a document, identify or elimi- nate the source of documents produced on machines, and preserve or restore the legibility of documents (SWGDOC, 2012). As with all other forensic scientists, upon completion of their examinations, they will write reports stating their conclusions and results and, if necessary, testify in court.

Questioned document examiners have one of the longest training programs of all forensic scientists. For example, the Illinois State Police training program for document examiners is nearly 3 years long. Much of this program length involves direct mentoring of the trainee, though there are many aspects of questioned document examination that require time and effort to learn as well—for instance, determining if a signature is forged, if a document has been altered, how to read indented writing and obscured writing, and how to differentiate ink and paper types (SWGDOC, 2015; Indiana State Police Laboratory Division, 2013).

Writing and Individualization When you learned to write, letters were probably displayed around the classroom, and your teacher instructed you in the process of duplicating the letters as you saw them. This is a typi- cal method of learning to write, exemplified by the Zaner–Bloser and Palmer methods (Sie- gel & Mirakovits, 2016). The result of this teaching method is that when students first learn to write, their writing is very similar. This is because teacher evaluations of students’ work involve similarity between the student writing and the examples being copied. This changes, however, as students develop their own style of writing, which will remain with them for most of their life. These differences begin after the students have developed skill in forming the letters and the teacher begins to evaluate them more on content, rather than the form of writing. The students then begin to bring personal characteristics into their writing through embellishments in the letters, training of their muscles, hand–eye coordination, and artistic flair. With practice, students develop what is called their unconscious writing style. While this remains fairly static, it is not permanently fixed, as fingerprints are. Health status, age, acci- dent, and other factors can cause changes in a person’s handwriting. Some can be acute, or temporary, such as when a person is hurried or under the influence of alcohol or drugs. Some can be chronic or long lasting, such as when diseases set in or other medical events happen, such as a stroke (Siegel & Mirakovits, 2016).

Even through this process, characteristics may remain that a document examiner can find and relate to a questioned document in a case. Help with these comparisons will be available in the form of standards.

Section 9.6Document Analysis

More recently, as keyboarding has replaced handwriting and typing in many areas of our lives, some educators have raised the question of whether cursive writing should even be taught in schools. In some places, it has already been dropped. It is probably fair to say that handwrit- ing is likely to play a smaller role in questioned documents examination than it did in the past.

Collection and Preservation In questioned document evaluations, the examiner must compare two types of documents. Those are questioned documents and known documents, also termed exemplars. A ques- tioned document is any document about which the authenticity or authorship is in some way questioned. This type of document could be a threatening letter, whose author law enforcement officials want to determine. It could also be a will on which the signature of the writer is in question. Other types of questioned documents include counter- feit money or artwork, altered checks, or any other printed material that may have been altered in some way.

The other document required by the questioned document examiner is a stan- dard of the writing from the suspect or machine that is being checked. The stan- dard or known writing can be given by the suspect freely, obtained under court order, or consist of a collection of business writ- ing. Collections of business writing may be found in the home of a suspect. They can include grocery lists, unmailed letters, journals, diaries, and checkbooks. Some- times, this writing may be gathered at the execution of a search warrant. This may be the only standard available, as in the case of a contested suicide note. Generally, the documents have already been written by the suspect and are collected to be com- pared to the questioned document.

Think About It

Do you have a handwriting sample from when you were younger? Or multiple writing sam- ples of someone as they’ve aged? Compare them. Can you distinguish any individualizing characteristics that have formed in the handwriting?

Associated Press Collecting comparison evidence is essential for document analysis. Without a comparison, handwriting experts have no basis for identifying whether a document was written by a suspect.

Section 9.6Document Analysis

Evidence found in cases in which the authenticity of a document may be in doubt will likely be paper based. The primary duty of the investigator is to preserve the document while main- taining the chain of custody. It may seem simple—place the document in an envelope and seal it. That may work for some items, such as suspected forged documents and obscured documents. However, a document may require specialized treatment or processing. Besides looking at the writing, this document could include fingerprints or DNA that could be of value. Knowing this, it is important to take a further look at handling and packaging the evidence.

Remember that most crime scene processing requires some use of personal protective equip- ment. Here, gloves will be required. Many documents can be sealed in clear plastic sheet pro- tectors. This will preserve fingerprints and DNA, as well as provide a view of the document for the examiner. However, chemical processes required for DNA extraction and fingerprint development can cause inks to run, destroying the writing. In these cases the document examiner will perform the first examinations on this evidence. The evidence must be exam- ined and photographed as a way to preserve it for court and maintain chain of custody, should any damage happen. This photography should be completed with scale markers so size is not an issue later. If the examiner wants to highlight some aspect of the document, she or he can zoom in on that part of the document. If the examiner wants to use a representation of the document in court, the photograph can be enlarged for the jury to see, as well.

After the document is in the sheet protector, the investigator must consider if the document will be processed for indented writing. Indented writing is discovered, for example, when writing is done on a pad of paper and then the marked page is removed. The page below, which appears blank, will have indentations from the writing that was applied to the page above. If the investigator places the pad of paper in an envelope and seals it, anything written on the envelope will transfer to the document, adding to the indentations and contaminating the evidence. Besides the sheet protector, something to cushion the evidence, such as thick paper or cardboard, will help preserve the evidence. This will help the laboratory get the most from document evidence.

Known documents must be collected, but how many? The simple answer is as many as pos- sible. Having the suspect fill out one handwriting exemplar will do very little to help a case. Imagine you have asked a person for handwriting samples. Any suspect who knowingly wrote the questioned document will disguise his or her writing on the exemplar, or use conscious handwriting. Repetition is the key to obtaining real, unconscious handwriting. As multiple copies of the same exemplar are completed, the suspect’s normal handwriting will eventually come out. It may take 10 or more copies, but it will happen, as boredom sets in. While there is no set guide for the number of exemplars, have the suspect complete as many as possible. Having multiple exemplars from a suspect provides the examiner with a lot of information for comparison. When collecting business, or nonrequested, writing, the same rule applies: get as many samples as possible.

Think About It

Do you think the same care should be taken with known documents? Why or why not?

Section 9.6Document Analysis

When the evidence arrives at the laboratory, the examiner will need some guidance for pro- cessing. It is up to the investigator to explain what the examiner should look for. Is the issue identification of the writer, as would be seen in an extortion note? Was a document thought to be altered in some way? Should the document be processed for fingerprints or DNA? This must be communicated to the examiner via the request for analysis. Following these guide- lines will help get the most from document evidence.

Analysis and Comparison Once the examiner has all of the evidence, analysis can begin. This is done through compari- son. The comparison and results are based on several factors that the examiner takes as premises. The first is that no two individuals have identical writing. Another is that all indi- viduals have variations in their writing, which can be caused by their mood at the time or the amount of time available to write.

Another consideration in handwriting comparisons is that no one has one truly unique aspect of their writing that, taken by itself, is individualizing. The document examiner must look for several characteristics—such as the slope of letters, angle of writing, spelling and use of words, and use of margins—that carry through from the questioned to known documents before reaching a conclusion. There is no set number of characteristics required by the ques- tioned document community. It is left to the individual examiner to determine when he or she has enough characteristics to judge the comparison.

Lastly, the document examiner must take into account any differences within the handwrit- ing contained in the known versus the questioned documents. One unexplainable difference can be enough to eliminate a suspect if it is distinct enough. Therefore, as with other types of pattern evidence, a conclusion will be reached by the examiner based on sufficient similar- ity between the known and questioned documents with no unexplainable differences in the writing.

Types of Analysis When dealing with documents not produced by a machine, there are several different analy- ses that can be completed by the document examiner. The most common is determination of the writer. If, for some reason, the author of a document is in question, the examiner can assist in finding the author. The examiner will need the document and as much known writing from the suspect(s) as can be obtained. Comparisons between the questioned and known samples

Think About It

Look at your own handwriting. A good place to find examples is in your checkbook. Look closely at the handwriting examples. Notice that they are not superimposable. They are all different, but you can recognize them as your handwriting. How does this help or hinder the document examiner? What can the examiner do to minimize any effects of this natural variation?

Section 9.6Document Analysis

can establish a link between the two or eliminate the suspect as the author. One of the most talked-about cases involving handwriting was the murder of JonBenét Ramsey.

Other cues document examiners can use are spelling, grammar, and writing style. The cur- sive writing of most Europeans, for example, is recognizably different from that of most Americans. In the notorious Lindbergh baby kidnapping case on March 1, 1932, investigators received a series of ransom notes presumably written by the kidnapper. The style and some of the spelling and usage suggested the writer was of European origin, possibly German. Eventu- ally, Bruno Hauptmann was arrested and tried for this crime. The ransom note writing backed up the state’s contention that he was guilty. He was convicted and later executed.

Sometimes a document may have been altered in some way. In these cases the knowns may help identify the writer, but of more importance is the alteration. If the alteration was writ- ten and different pens were used, the analysis may involve the use of alternate light sources such as ultraviolet or infrared lighting. Different formulations of ink can respond differently to light.

Another type of alteration is obliteration, or erasing writing from the document. The exam- iner will be able to tell if writing has been erased but may not be able to restore what was written. If simply obliterated using another ink, use of alternate lighting may help see through the obliterating medium.

Indented writing can be useful if the questioned document has not been found but a pad of paper is found from which the document may have originated. In this case the pad should be packaged and sent to the laboratory, which should be asked to conduct indented writing analysis. An electrostatic detection apparatus can be used to visualize writing that may be nearly invisible otherwise. Placing the evidence in the device and covering it with a thin sheet

Case Illustration: The Murder of JonBenét Ramsey On December 26, 1996, Patsy Ramsey found a note on three sheets of paper at the bottom of a stairway in the Ramsey home. She read the note, which stated that JonBenét had been kidnapped but was safe. She checked the bedroom and found 6-year-old JonBenét missing. The police were called, and the investigation started. The note was placed in evidence, and standards were taken from several people, including Patsy and John, the father of JonBenét. Comparisons excluded the Ramseys, and to date, there has been no one confirmed as the author of the letter. Additionally, there was a pad of paper that had indented writing found in the Ramsey home. The writing was the same as the ransom note and could not be identi- fied as that of any of the suspects’. Later, after a police search, the body of JonBenét was found in the basement. The crime scene at this point was compromised, and evidence may have been contaminated or gone missing. In the intervening years, several people have been tested and were found not to be the author of the note. The case still goes unsolved, even though there was also genetic material for DNA evidence.

Reflect On It With the evidence collected, is there any way this case can ever be solved? Why do you think no one has ever been caught and convicted?

Conclusion

of plastic is the first step. The paper and plastic are held in place in the instrument by vac- uum. Fine powder is placed on the plastic sheet, and an electrostatic charge is placed in the paper and plastic. The powder sticks where the charge is concentrated the most—in this case, where indentations are in the paper. After removing excess powder, the indented writing can be read. Care must be taken not to contaminate the sheet to be processed. The sensitivity of the instrument is such that even minor indentations can be visualized.

Documents produced by machine can be examined and compared, especially if the writing was placed on the document through impact. This is because damage to the letters or mis- alignment of the devices that transfer the writing to the document cause unique defects to the printed document. This includes typewriters of all types and printers that use impact transfer methods, which work, for example, by keys striking the typewriter ribbon and the paper to transfer the ink to the paper. These strikes cause physical defects that, when developed, can be used to identify a particular printer or typewriter as creating the document. Printers that do not use impact technology, such as laser printers or ink-jet printers, have very little pos- sibility of developing the kind of defect that can be compared. The same is true for photocopy machines. These devices may not be traceable through the print, but some information may be gained through chemical analysis of the inks or toners. Different manufacturers use pro- prietary formulations, which may narrow the options down to a particular manufacturer of a machine. Individualization would be very difficult, however (Gaensslen, Harris, & Lee, 2008).

The conclusions reached by a questioned document examiner are very similar to those reached by other pattern analysis examiners. Examiners may be able to say that a person wrote a particular document. They can also conclude that a person did not write the docu- ment. If insufficient characteristics exist to make a determination, they may have to report that the results are inconclusive. If documents are altered, obliterated, or include indented writing, examiners can tell what was changed or hidden. Questioned document examiners working under SWGDOC guidelines do not give psychological profiles based on handwriting; this practice is called graphology. Forensic document examiners will only give results based on their observation and analysis of the documents, both questioned and known, to provide answers to law enforcement on who wrote or altered the document, nothing more.

As a result of some of the court challenges against the reliability of document analysis, there have been efforts by researchers to help validate the work and results of questioned docu- ment examiners and also to construct pattern-recognition models that can get at handwriting differences (Srihari, Cha, & Arora, 2002; Kam & Lin, 2003). At this time, in spite of the chal- lenges, document analysis is still accepted in the courts.

Conclusion This chapter covered more of the different types of pattern evidence for individualization, particularly firearms, tools, and document evidence. Comparison of fired evidence to fire- arms has been used for years to help determine if a particular firearm has been used in the commission of a crime. Despite the variety of firearms, a case involving them can be helped using cartridge casings, bullets, gunshot residue analysis, and the aide of databases such as IBIS and NIBIN. There are also a number of different tool marks that can be made with one tool. Using a comparison microscope can help identify a particular tool to a mark. Similar to firearms and tool mark evidence, handwriting can also sometimes be individualized. The

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individuality of a person’s handwriting has helped determine the authenticity of documents, and additional analysis by the document examiner has helped determine the authenticity of the document itself.

While all of these analyses have been used in the field of forensic science for many years, in recent years, court challenges have attempted to cast doubt on the science involved with these evidence types. The research that has taken place in these fields has confirmed the individuality of the striations found in the barrels of guns, the imperfections on tools, and the differences in handwriting between individuals. This evidence will continue to be used now and in the future to assist law enforcement and the courts in reaching conclusions to crimes that have been committed using firearms, tools, or the written word.

Key Ideas

• Firearms and tool mark evidence are important classes of physical evidence. • Important patterns for individualization include those left behind on fired evidence,

in tool marks, and in writing. • Rifling was added to the barrels of firearms to impart spin to the bullets, which

increased accuracy and range. Additionally, this process impressed into the barrels of firearms individualizing characteristics that help connect a bullet and/or car- tridge casing to a particular firearm.

• Bullets can be identified to a particular weapon using a comparison microscope to examine the individual characteristics.

• Gunshot residue can be identified on the hands of a person, but this finding does not show that the person fired a weapon.

• IBIS and NIBIN systems enable rapid search and retrieval of fired evidence from dif- ferent cases.

• Handwriting is individual. With very rare exceptions, identifications or exclusions can be made following a comparison by a qualified examiner, if sufficient evidence and appropriate standards are available.

• As stated by SWGDOC, document examiners can determine the authenticity of a document, include or exclude a person or machine as the source of the writing, and preserve or restore the readability of a document.

• Different types of light (such as ultraviolet or infrared lighting) may detect altera- tions in a written document, while the electrostatic detection apparatus can help make indented writing visible.

Critical-Thinking Questions

1. You are a firearms examiner testifying in court. Explain to the court how it is possi- ble to trace fired evidence back to a particular revolver. How would your explanation differ for a pistol or a shotgun?

2. In the Sacco and Vanzetti case, would proper chain of custody have helped? 3. Do you think that cartridge cases from a revolver will pick up individual characteris-

tics from the breech face like those in a semiautomatic pistol? How about ejector and extractor markings?

4. You have three fired projectiles and four cartridge cases from a crime scene. How would you package them?

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5. You have gotten a hit in the NIBIN database indicating that a bullet from your case matches a gun from another crime. Can you send out the report stating the match with this information? What would be the next steps?

6. Depending on the direction and pressure used, one tool can make different types of marks, which can make it difficult to identify a particular tool to a tool mark. Do you think this makes this type of evidence less valid in a case or in court? Why or why not?

7. You are a document examiner and have been given a kidnapping note, a writing pad that might have been used to write the note, and several exemplars from the suspect (these include a grocery list, a to-do list, and a statement written while in police cus- tody). How would you go about examining these documents?

8. How would you explain to someone how handwriting can be individualized? What about a written document from a machine?

Key Terms automatic firearm A firearm design that continually fires when the trigger is depressed and there are cartridges ready to be fired. These are also called full automatic weapons and machine guns.

ballistics The physics of projectile flight along a trajectory or path.

breech face The part of the breechblock or breech bolt that holds the cartridge in the chamber; it is against the back end of the cartridge case or shotshell, which contains the primer during firing.

breech face markings Marks from the breech face that are caused by recoil from firing the cartridge; these have been used to identify a cartridge case with a specific firearm.

bullet The projectile discharged from a firearm that is firing a cartridge.

caliber The diameter of the barrel of a fire- arm measured from the top of a land across to another land and expressed in millime- ters or hundredths of an inch.

cartridge A single unit of ammunition, con- sisting of the case, primer, and propellant, with one or more projectile(s). Also applies to a shotshell.

cartridge case The portion of a cartridge remaining after it has been fired.

comparison microscope Essentially, two microscopes connected to an optical bridge, allowing the viewer to observe two objects simultaneously with the same degree of magnification. This instrument can have a monocular or binocular eyepiece.

cylinder The rotating part of a revolver that contains the ammunition.

fired evidence Bullets, cartridge cases, and shotshell cases.

general rifling characteristics (GRC) The number, width, and direction of twist of the rifling grooves in a gun barrel.

groove The lowered portion between the lands in a rifled bore.

indented writing The concave marks that are sometimes made on a surface that was underneath paper (or other material) that was written on.

Integrated Ballistics Identification Sys- tem (IBIS) A database developed by Foren- sic Technology Incorporated to assist in the comparison of fired evidence.

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land The raised portion between the grooves in a rifled bore that is the remain- ing portions of the original bore of the gun before rifling was completed.

magazine A container for cartridges that feeds them into the chamber. The magazine may be detachable or an integral part of the forearm.

mandrel A shaped metal rod or bar used as a core around which the rifling of a barrel may be formed.

obliteration The act of using some ink or other compound to completely cover writ- ing on a document.

projectile An object that is propelled. In the case of firearms, it is propelled by the force of rapidly burning gases or other means from a firearm and is typically called a bullet.

propellant The explosive material that generates the force necessary to propel a bullet from a gun, including black powder and others.

revolver A firearm, usually a handgun, that includes a rotating cylinder with several chambers that allows bullets to be fired one at a time.

rifle A firearm having rifling in the bore and designed to be fired from the shoulder.

rifling (groove) Helical grooves in the bore of a firearm barrel to impart rotary motion to a projectile. The effect resembles the stripes in a candy cane. These impart the individual characteristics to bullets fired from the firearm.

semiautomatic firearm A repeating fire- arm of a design that requires the trigger to be pulled for each shot fired and that uses the energy of discharge to perform a portion of the operating or firing cycle (usually the loading portion).

shearing Pertaining to tools that cut sheet or bar metal between two blades that pass immediately adjacent to each other.

shotgun A long gun that does not have rifling in the barrel. It mainly fires pellets from a shotshell and, occasionally, large solid projectiles known as slugs.

shotshell A cartridge intended for use in a shotgun.

shotshell case The portion of a shotshell remaining after it has been fired.

test fire The firing of a firearm in a labora- tory to obtain bullets and cartridge cases that will be used by the examiner to com- pare to the bullets and cartridge cases col- lected at a crime scene.

Web Resources Website for the NIST OSAC Firearms and Toolmarks Subcommittee: https://www.nist.gov/topics/forensic-science/firearms-and-toolmarks-subcommittee

Website for the Scientific Working Group for Forensic Document Examination (SWGDOC): http://www.swgdoc.org

Website for the NIST Forensic Document Examination Subcommittee: https://www.nist.gov/topics/forensic-science/ forensic-document-examination-subcommittee

Conclusion

Internet search results for ransom note and exemplars in the JonBenét Ramsey case: http://www.bing.com/image/search?q=jonbenet+ramsey+ransom+note&form=MSNH14& pq=jonbenet+ramsey+&sc=8-16&sp=6&qs=AS&sk=AS5

This is the response by SWGGUN and the AFTE to 25 foundational firearm and tool mark examination questions from the Subcommittee on Forensic Science, Research, Develop- ment, Testing, & Evaluation Interagency Working Group. This response is a compilation of published research that addresses each question.

Murdoch, J. (2011). Email cover letter composed by chairman John Murdock. Committee for the Advancement of the Science of Firearm and Toolmark Identification. Retrieved from https://afte.org/uploads/documents/position-rdte-iwg-2011.pdf