A crime scene must be searched thoroughly and systematically to avoid accusations of negligence. The search method used depends on the size and location of the scene. Common search patterns include spiral, grid, line, and quadrant searches. Evidence must be carefully collected and packaged to prevent changes and contamination. Proper documentation of the chain of custody is also crucial.

1. Searching the crime scene
A systematic approach

2. Searching the scene
• The search for physical
evidence must be
thorough and systematic
• If the search is not done
systematically, and in a
timely manner, then
charges of negligence or
accusations of a cover up
may be filed

3. How to search
• How a crime scene is processed depends
largely on the locale and size of the crime
scene
• When possible, it is beneficial to have a
person for supervising and overlooking of
collection procedures
• Some general rules apply to all
investigations such as searching for points
of entry and exit first and foremost.

4. How to search
• There are several
different methods for
collecting physical
evidence
• Generally these are
chosen based on
experience and logic

5. Spiral search method

6. Spiral search method
• Generally used for large search areas with
very few individuals involved in the search.

7. Grid search method

8. Grid search method
• Generally used for large search areas with
numerous searchers.
• Often used in open fields and woodland
areas

9. Line search method

10. Line search method
• Generally used in medium sized search
areas with very few searchers.

11. Quadrant search Method

12. Quadrant search Method
• Used in small search areas where minute
details are very important

13. Collection of evidence
• Evidence must be collected and handled in a way that
prevents any change from taking place between the time
it is removed and the time it arrives at the lab.

14. • Removal of any physical evidence, such
as hairs, fibers, soil, etc., should not
happen until the evidence is in the lab
• Each different item, or similar items
collected at different locations, must
placed in separate containers.

15. Collecting tools
• The tools used in the
collection process are
as important as the
collection itself.
– Using the incorrect
tools can result in
contamination

16. • Collection tools also
include the packaging
devices.
– In general manila
envelopes, pill bottles,
and cardboard pill
boxes are suitable

17. Collecting blood evidence
• When collecting blood evidence what type
of container should you use?
• If you use an airtight container then the
condensation is conducive to mold growth
and can ruin evidence.

18. Collecting burned material
• Collection of burned material must be
placed in an airtight container because of
the possibility of losing volatile substances
that could have been used in an arson
case.

19. Chain of Custody
• A written log of where evidence is and
who may have it, must be kept at all times.
• Any break in the chain will result in the
evidence being inadmissible in court