The Crime Scene

Errors at the crime scene in protecting, gathering, and processing evidence can

NEVER BE CORRECTED!!!

First responder (usually a uniformed police officer): 1. Medical assistance is first priority…protecting evidence is

secondary!2. Protect scene…nothing new added or altered, nothing removed.3. Detain suspects/witnesses.

Medical examiner:4. Note condition of body, estimate time of death.

Crime Scene Investigator:5. Interviews first responder, victims, witnesses6. Record details (weather, odors, light, visibility, etc)

A. Preserving and Isolating the Crime Scene

ADAPTAssess crime scene

Detain witnesses

Arrest perpetrator

Protect the scene

Take notes

B. Observing and Documenting the Scene

1. Notes; Thorough, complete, clear, legibleMeasure distances, date/time and description of everythingInclude full names and addresses of all peopleMay tape-record descriptions

2. Photographs and videotapes; Unaltered crime scene Overviews and close-ups, use rulers to show scale

3. Sketches; Give measurements, scale, relative placement of details Date and Time, reference points, all relevant names Never add/subtract details from an original sketch

C. Searching the Scene for Evidence

Anything that could carry trace evidence or anything that should not be there.

Use extreme care in identifying, packaging, and labeling each piece of evidence.

Special lighting may help show body fluids.

Four standards for admissible evidence:

(a) Legally obtained

(b) Relevant

(c) Identify the item

(d) Maintain the chain of custody

Search methods:

A. Spiral

B. Grid

C. Line or Strip

Works well in Large areas

D. Quadrant or Zone

(1) INTEGRITY – sample is preserved and uncontaminated

(2) GENERL RULES – use separate containers, label each item, beginning with the most fragile (such as fingerprints, bloodstains, etc)

D. Collecting and Packaging Physical

Evidence

•Wear sterile vinyl or latex gloves•Wet items dried first•Containers sealed tightly•Biological items dried and frozen•Clothing with trace evidence, entire garment bagged•Firearms inside a wooden box and fixed in place to prevent movement •Arson evidence in airtight containers to prevent evaporation or dispersal of fumes•Adhesive tape and small vacuums pick up EVERYTHING (not just the evidence)•Tweezers, pens, uncontaminated objects to pick up evidence

Also consider…

example…CARPET SAMPLES FROM AN AREA THAT WAS AFFECTED BY FIRE AND THE SAME CARPET FROM AN AREA THAT WAS UNAFFECTED BY FIRE

Obtain controls

E. Maintaining the Chain of Custody

Written record of everyone who has had contact with the evidence from the time of collection to the time it may appear in court.

F. Submit evidence to the laboratory

SAFETY

2x

A likely sequence of events based on physical evidence and statements made by any witnesses

Reconstruction of the Crime

1. Crime scene processing, recognition, documentation, and collection.

2. Identification and Classification of evidence…goal is individualization of as much of the evidence as possible using comparison testing, evaluation, and interpretation

3. Attempt to reconstruct the crime.

4. Report and present all findings in a logical and convincing manner.