Discussion Question

Shelby2008!

Chapter4ogle.pptx

Home >Law homework help >Criminal homework help >Discussion Question

Crime Scene Investigation and Reconstruction

Fourth edition

Chapter 4

Crime Scene Sketches

Value of Sketches

An essential supplement to the investigator’s notes and photographs

Provide precision with regard to spatial relationships of items seen

Provide a visual model to illustrate the investigator’s testimony in court

Objectives of Crime Scene Sketches

Present a clear “mind’s eye” picture of the scene

Complement the investigator’s notes and photographs

Show the accurate location and relationships of the evidence items

Objectives of Crime Scene Sketches

Refresh the memory of the investigators

Illustrate the testimony of witnesses

Provide factual data for crime scene reconstruction

Rules of Thumb for Sketches

Plan systematically for sketching the scene

First roughly show the overall layout of the scene

Prepare detailed sketches of pertinent area with measurements

Prepare blowup sketches as necessary

Additional sketches

Points to Keep in Mind

Show compass point on sketch

Make accurate measurements for all evidence items

Use equal accuracy for measurements for items on the same sketch

Use fundamental methods for measurements

Make sure that the tape is straight and does not sag when the measurement is taken

Have two individuals verify all measurements

Avoid Common Errors

Reading numbers upside down

Reading the wrong foot mark

Confusing the zero point of the tape

Reading tenths of a foot for inches

Rough Sketches

The detailed sketch is what the term “sketch” or “diagram” usually refers to when referencing a crime scene sketch

This sketch is hand drawn at the scene

Contains measurements for all evidence item locations and other pertinent objects such as furniture

Rough Sketches

The locality layout illustrates the general area in which the crime scene occurs

Designed to provide an overview of the crime scene

Locality Layout Sketch

Small Area Sketches

The Blowup Sketch

Allows for higher accuracy of measurements for blood spatters, bullet trajectories, or other pattern evidence

Blowup sketches are detailed sketches of small areas inside a larger sketch

Blowup Sketch

Exploded View Sketches

Used to illustrate the interrelationships of blood spatters, bullet holes, and trajectories or other patterns of significance

Shows the walls (and occasionally the ceiling) lying flat (folded down)

Elevation Sketches

Show the slopes present in the scene

Are rough sketches made in order to show the elevation perspective of a crime scene

An elevation drawing is a rough representation of the terrain without elevation measurements and is a supplement to photographs

Elevation Sketches

Finished Sketches

Finished sketch (not to scale)

Finished sketch (drawn to scale)

Not to Scale Sketch

Critical Accuracy

Manually drawn sketches

Professionally drawn sketches

Computer-drawn sketches

Computer-Drawn Sketch

Courtroom Display Sketches

For courtroom display purposes only

Represent a wide variety of sketches

Simple sketch drawn to scale

A very large drawing in color

Prepared by an architect or a professional graphics artist; or, in some cases, they may be computer-drawn

Three-dimensional Computer Drawn Sketches

Are especially helpful to the individual preparing a crime scene reconstruction

Permit viewing of the scene from a number of different aspects, from side views at differing angles to overhead viewing

Preparation: Suggested Procedure

Should follow the same sequence followed in the initial survey of the scene

The crime scene investigator should first prepare the layout sketch in order to provide a framework

A rough sketch should be prepared for each area containing pertinent objects or evidence

Preparing the Sketches

Measure dimensions of each area accurately

Two individuals should verify all measurements

Each evidence item requires measurements to at least two fixed points

Preparing the Sketches

Measure the dimensions and location of furniture and other objects pertinent to the scene

Measure the location of windows and doors; show the direction of the door opening

Label furniture and other objects with letters

Preparing the Sketches

Label evidence items with numerals; and place labeled items in the legend with their measurements

Check each sketch for accuracy and completeness

Measurement Techniques

Rectangular coordinates measurement method

Triangulation measurement method

Secondary reference points measurement method

Transecting baseline measurement

Polar coordinates measuring method - Software mapping technique

Rectangular Coordinates Method

Triangulation Method

Transecting Baseline Method

Polar Coordinates Method

Mapping Technique Method

Personnel Requirements

A three person team is the most efficient approach for preparation of sketches

One prepares the sketches while the other two take measurements

Equipment Needed

Tape measures- metal are preferred because they are the most accurate, sag the least and are the easiest to handle

Discussion Question

image2.png

image1.png

image3.jpg

image4.jpg

image5.jpg

image6.jpg

image7.jpg

image8.jpg

image9.jpg

image10.jpg

image11.jpg

image12.jpg

image13.jpg

image14.jpg

image15.jpg