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Instructor Name

Date, Semester

Chapter 3:

Recording the

Crime Scene

Crime Scene Notes

Note-taking begins when the investigator is contacted and requested to report to the crime scene.

The crime scene notes should begin with:

1)The identity of the person who contacted the investigator

2) Time of contact and arrival at the crime scene

3) Preliminary case information

4) Personnel present on arrival and those being contacted

Crime Scene Notes

Notes contain a personnel log, all observations made by the investigator, and the time observations were made.
Notes are taken in a uniform layout, concurrently as the observations are made.
Notes are written in a bound notebook in blue or black ink.

Crime Scene Notes

Investigators may choose to record crime scene notes on audio tapes.

This leaves the hands free to process the scene as the notes are taken.
Tape-recorded notes must eventually be transcribed to a written document.

Photography

Photographs taken at a crime scene:

1) Show the layout of the crime scene

2) Show the position of collected and uncollected evidence

3) Show the point of view of victims, suspects, and witnesses

4) Show the original condition of items of evidence at the scene

PHOTOGRAPHY

Figure 3-4

Film Photography

Film consists of a sheet of silver halide grains which “expose” when exposed to light.
Film speed is a measure of the light-gathering capacity of the film.
Special types of film include Polaroid film and Infrared film.

Digital Photography

A digital photograph is made when a light-sensitive microchip captures light on each of millions of tiny picture elements, called pixels.
The light is recorded on each pixel as a specific electric charge which is read by the camera as image information which is stored as a file on a memory card.
The number of pixels is directly related to the resolution of the picture. Photographs with more pixels show increasingly good resolution, or more detail and sharpness in photographs.
The number of pixels that a camera features is usually measured in millions of pixels, or megapixels.

Cameras

The most commonly used camera at crime scenes is the Single Lens Reflex (SLR) camera or the Digital Single Lens Reflex (DSLR) camera.
SLR and DSLR cameras allow for the use of various accessories such as lenses, flashes, and filters.
SLR and DSLR cameras also allow for manual adjustment of camera settings, such as aperture and shutter speed, that affect image quality.

DSLR Modes

The “auto mode” automatically selects an appropriate f-stop and shutter speed for conditions being photographed.
The “sports mode” captures subjects in motion by using a higher (faster) shutter speed.
The “night mode” uses a lower (slower) shutter speed to gather as much light as possible to create the image.
The “landscape mode” automatically selects higher f-stops to improve depth of field.
The “portrait mode” selects lower f-stops to decrease the depth of field and make the subject stand out clearly against a blurred background.

Lenses

The camera lens bends light to focus an image on the film or digital microchip.
The lens’s focal length, the distance between the lens and the image projected on the film or microchip, determines the area shown in the resulting photograph.
Normal Lens

Focal length of 50-55m

Used for most photographs that need to be taken at a crime scene because it can show as much area as half a wall

Filters

Barrier filters block one specific wavelength (color) of light from reaching the film or microchip, making areas of that color appear lighter in the photograph.

Bypass filters allow only a small range of wavelengths of light to reach the film or microchip and block all others.

Lenses

Telephoto Lens

Focal length of 100 mm or greater
Used to magnify images

Wide-angle Lens

Focal length of 35 mm
Used to show much more area in one photograph than a normal lens

Macro Lens

Focal length of less than 50 mm
Used for highly-detailed close-up photographs

Multi-purpose Lens

Focal length from 28-80 mm used to take normal, wide-angle, and telephoto photographs

Aperture and Shutter Speed

The camera aperture is a measure of the diameter of the opening of the diaphragm, which allows light to reach the film or microchip.
On film or digital cameras, one adjusts the aperture by setting the f-number.

The lower the f-number setting, the wider the aperture and the more light is allowed in.

The shutter speed is the length of time that the film or microchip is exposed to light.
The shutter speed is measured as a fraction of a second by factors of 1/2 (i.e. 1/2, 1/4, 1/8, etc).

Depth of Field

The depth of field shown in a photograph is the amount of area in the foreground and background of an object in focus that is also relatively in focus.

The smaller the aperture opening, the greater the depth of field will be. This means that higher f-number settings will yield higher depth of field.

Illumination

The color temperature of a light source is “hot” if it has a bluer hue, while a “cold” light source has a red-orange hue.
Light meters on film or digital cameras allow photographers to measure the amount of light in a shot.
A flash unit can produce either direct reflective lighting or oblique lighting, which is achieved by positioning the flash at an angle less than 90° to the surface to show detail.

Tripods

Using a tripod eliminates the possibility of blurred photos resulting from unsteady hands.

For crime scene photography, it is useful if the tripod has:

1) Independently adjustable legs suitable for uneven terrain

2) A level to ensure 90º images of evidence

Crime Scene Photography Log

A detailed log of each photograph taken at the crime scene is kept by the crime scene photographer.

The top of the photography log form includes:

Case number
Type of scene
Date
Location of scene
Description of the camera and lenses being used
Film type and speed (if applicable)
The photographer’s name and title

James O'Sullivan (JO) - If possible add a photo of a Crime Scene photography log. Would be easier for the students to understand.

Crime Scene Photography Log

For each photograph, the log records:

Date and time the photograph was taken
The location of the picture
The f-stop and shutter speed settings
The lighting used and the lighting angle (if applicable)
A brief description of the subject of the picture

Basic Guidelines

Photograph scene in unaltered condition
Fill the frame
Avoid shadows in the photograph
Maximize depth of field
Photograph scene in a logical sequence
Keep a log

Crime Scene Photography

The four minimum photographs required at a crime scene are:

An overview photograph
A medium range photograph
A close-up photograph
A close-up photograph with a scale

Crime Scene Photography

Overview photographs of the entire scene and surrounding area, including points of exit and entry, are taken first.

Taken from the outside borders of the scene and from various angles
If the crime scene includes a body, photographs must show the body’s position and location relative to the entire scene.
Include a “visual tag,” an object recorded in multiple overview photographs, to help visually piece the scene together.

Crime Scene Photography

Medium-range photographs show the layout of smaller significant areas of the crime scene.

Taken with evidence markers in place to show the spatial relationships between and among pieces of evidence in greater detail than the overview photographs.
Include at least one photograph of the “center” of the scene.
In violent crimes, this usually includes the site where the victim was found and the surrounding area.

Crime Scene Photography

Close-up photographs are taken last and show greater detail of individual objects or evidence.

Taken at a 90º angle to the object, with and without evidence markers and scales.
Scales should be placed as close to the evidence as possible without affecting it in any way.
After the 90º photographs have been taken, photographs from other angles may be taken.
The most important close-up photographs are those depicting injuries and weapons lying near a body.
After the body is removed from the scene, the surface beneath the body should be photographed.

Special Crime Scene Photography

Night photography requires the use of external lighting or “painting with light.”
Indoor photography requires photographs of the neighborhood, points of entry and exit, and all walls, floors, and ceilings.
Outdoor photography requires location of photographs to be recorded by a Global Positioning Device or measurements from landmarks.

May include aerial photographs

James O'Sullivan (JO) - If possible add examples of the various types of Special Crime Scene Photography

Special Crime Scene Photography

Arson photography requires photographs of the point of the fire’s origin and use of special equipment or techniques to provide maximum contrast in photographs of charred areas.

May also include photographs of crowd outside scene because arsonists commonly return to scene

Sexual assault photography requires photographs of all wounds and clothing while showing discretion to the victim.
Impression photography requires oblique lighting to show details and a scale to later create a 1:1 scale photograph for comparison to footwear or tire samples.

Special Crime Scene Photography

Bloodstain photography requires photographs of all pertinent stains and determined area of convergence or area of origin.

Bloodstains treated with luminol photographed in complete darkness

Latent fingerprint photography require photographs with a 1:1 scale using a special latent fingerprint camera or a regular camera fitted with an adapter.

Black and white film used to show greater contrast

Digital Crime Scene Photography

Digital images are easily manipulated using computer programs and may not show an accurate depiction of the crime scene.
Digital images may lose image data or details through compression.
Digital images are preserved by either lossy or lossless compression.

Lossy compression condenses files by discarding some image information. The information lost during this compression is irretrievable.

Lossless compression condenses files without discarding information so no important image information is lost. For this reason, all digital crime scene photographs should be saved by lossless compression to avoid losing any important information contained in those images.

Digital Crime Scene Photography

Law enforcement agencies ensure the admissibility of digital crime scene photographs by:

Developing Standard Operating Procedures that must be followed
Saving images to writable (not rewritable) disks by lossless compression
Saving enhanced or altered images as separate files
Keeping a detailed and accurate photography log
Submitting testimony from the crime scene photographer as to the accuracy of the digital images

Videotaping Crime Scenes

As with still crime scene photography, the crime scene video must include overview, medium-range, and close-up images.
A narrated crime scene video combines photography and notes.

However, it is important that only one person narrates and no side conversations are captured on the video.

Some video cameras can produce still photographs, but the quality is often poor.

Therefore, still photographs from a film or digital camera are still required.

Sketching the Crime Scene

Crime scene sketches

1) Clearly show the layout of a crime scene

2) Illustrate the relationship in space of all significant items and features

3) Clarify objects and features already described in notes or shown in photographs

4) Show measurements over long distances and topography of outdoor scenes

5) Depict possible paths of entry, exit, and movement through the scene

6) Demonstrate whether the account of a victim, suspect, or witness is feasible

The Finished Crime Scene Sketch

A rough sketch is created at the crime scene and contains an accurate depiction of the dimensions of the scene and shows the location of all pertinent objects and features.

All rough sketches include:

1) Title block with information on the case, crime scene, and person creating the sketch

2) Legend with identity and dimensions of objects in the sketch

3) Compass showing the North direction

4) Body containing the sketch itself

Points of reference for objects can be shown by the rectangular, triangulation, baseline, or polar coordinates method.

The Rough Crime Scene Sketch

The finished sketch is created from the information in rough sketch, but it is drawn to scale with care and concern for appearance.
The current standard method utilizes Computer-Aided Drafting (CAD) programs to create the finished sketch.
CAD programs also allow for the creation of three-dimensional finished sketches.