1. The Crime Scene

2. Physical Evidence and the Crime Scene
Physical Evidence – any object that can establish that a crime has been committed or can link a crime and its victim or its perpetrator.

3. Securing and Recording the Crime Scene
Secure and Isolate the Crime Scene.
The responsibility of the first responding officer.
Priority is medical assistance to any individuals in need and arrest of any perpetrator.

4. - The scene should be unaltered - Objects should be photographed
Record the Scene
A. Photography
- The scene should be unaltered
- Objects that have been moved
or removed must not be replaced
- Objects should be photographed
showing their position and
location relative to the entire
scene.
- Videotaping can augment but does
not replace still photographs.

5. B. Sketches Rough Sketch – A sketch drawn at
the crime scene, that contains an accurate depiction
of the dimensions of the scene and shows the location of all objects having a bearing on the case.

6. Finished Sketch - A precise rendering of the crime scene, usually drawn to scale.

7. Notes
- Must be constant throughout
- Must include a detailed written
description of the scene with
the location of items of
physical evidence recovered.
- Must identify the time an item of
physical evidence was
discovered as well as who and
how it was collected.

8. Dealing with Physical Evidence
There are specific procedures for finding, collecting, and transporting physical evidence.
Conduct a Systematic Search for Evidence
- How a crime scene is searched is dependent on the locale and size of the area as well as the actions of the suspect(s) and victim(s) at the scene.

10. Collect Physical Evidence - Can be anything from very tiny
to very large.
- Clothing from all persons
present at a crime scene may be
necessary.
- Critical areas should be vacuumed
and the sweepings
submitted to the
laboratory
for examination.

11. Efforts should be made to avoid changing evidence in any way.
Each different item or similar items collected at different locations must be placed in separate containers. Packaging evidence separately prevents damage through contact and prevents cross-contamination.

12. Forcepts may be used to pick up small items.
Packaging materials may include plastic pill bottles, manila envelopes, and plastic bags.
If the materials are too small for the container, a paper bindle may be used to keep the specimen contained.
Wet items must not be packaged in airtight containers as they may grow mold which contains its own DNA.

13. Fire evidence must be placed in an airtight unbreakable container to prevent the evaporation of volatile petroleum residues.

14. Maintain the Chain of Custody
Chain of Custody – a list
of all people who came
into possession of an item
of evidence.
Obtain Standard
/Reference Samples
- physical evidence whose
origin is known such as
blood or hair from a
suspect, that can be
compared to crime-scene
evidence.

15. Proper standard/reference samples, such as hairs, blood, and fibers must be collected at the crime scene and from appropriate subjects for comparison purposes in the laboratory.