1. The Crime Scene .

2. Fundamental Practices at a Crime Scene
Secure and Isolate Crime Scene
Record Crime Scene
Photograph Crime Scene
Sketch Crime Scene
Maintain excellent Notes
Conduct Systematic Search for Evidence
Collect and Package Physical Evidence
Maintain Chain of Custody
Obtain Standard/Reference Samples
Submit Evidence to Lab
Maintain Safety at Crime Scene
How do CSIs maintain safety at a crime scene?

3. Secure and Isolate Crime Scene
Responsibility of the first officer arriving on the scene:
Apprehension of any possible threat.
Medical assistance must be given to anyone in need
Scene must be preserved and protected because every person entering scene is a potential destroyer of evidence (intentionally or accidentally)
No unauthorized personnel (including spectators, unauthorized police officers and media) on scene
Ropes, tape, barricades used to secure scene
Record maintained of all people entering and leaving crime scene
What are some possible threats that need to be secured?

4. Record Crime Scene
Once the crime scene is secure, the lead investigator evaluates the area. There is a very limited amount of time to process scene before it gets disrupted by various personnel
Boundaries of crime scene determined
Initial walk-through conducted
Strategy developed to process scene
Photograph and/or sketch scene
Take detailed notes
Why must the crime scene be processed within a short period of time?

5. Photograph Crime Scene
Photographs must be taken without altering the scene or moving objects (unless there are injured people that need medical attention).
If anything gets moved, photos may not be admissible in court as evidence.
Detailed notes should be taken to override this issue.
If you were the crime scene photographer, what protocol would you use to document the scene?

6. Photography cont’d.
Crime scene must be photographed thoroughly (from various angles)
All adjacent areas as well
All points of entry and exit
If scene includes body, pictures of the position and location relative to entire scene must be taken
Close-ups of injuries, weapons
Once body is removed, the surface under body must be photographed
Each piece of physical evidence must be photographed in its original location next to a ruler or other measuring device AND a number I.D. card
Video recorders are also being used these days, but have not replaced still photographs

8. Carmin Ross-Murray .

9. Carmin Ross Crime Scene

10. Sketch Crime Scene
Once photographs are taken, the crime-scene investigator will sketch the scene (a rough sketch, since there is no time to make a polished one)
A rough sketch employs geometric shapes and letters and numbers.
A finished sketch is created with mush more care and detail. Computer aided drafting (CAD) can be employed to do this.

11. Rough Sketch

12. Finished Sketch – Hand Drawn

13. Finished Sketch (CAD)

15. Maintain Excellent Notes
Must be a constant activity
Must include a written description of scene and location of all objects of physical evidence
Tape-recorded notes can be more advantageous – faster. But at some point in time the tapes must be transcribed into written/typed notes.

16. How do CSIs search a crime scene
How do CSIs search a crime scene? Conducting Systematic Search for Evidence
Physical evidence may be large or microscopic, therefore searches have to be conducted with extreme care and have to be thorough.
Hap-hazard searches will lead to important clues being missed or lost.
Systematic searches, using specific patterns are used.
Critical areas of the scene may be vacuumed with portable vacuum cleaners equipped with special filters
The search for physical evidence must extend beyond the crime scene to the autopsy room of the victim – the medical examiner will contribute to the evidence list with results of toxicology and pathology examinations of various body parts, organs, tissues, etc.

17. Factors affecting search methods
Environmental parameters (weather/climate, time of day)
Object being searched for and size
Number of personnel available
Terrain (trees, buildings, asphalt, grass)
Exigency (trumps detailed search): missing children, loaded weapon
Swath (effective area covered) size

18. Spiral Search

19. Grid and Zone
Also called the Quadrant Method

20. Parallel

21. Napa County sheriff’s office personnel looking for evidence in the vineyard where a fatal shooting took place.

23. Questions In what type of crime scene would you use:
1. A parallel search pattern
2. A spiral search pattern
And why?
3. Do you have to use the same search pattern in all areas of the crime scene? Explain your answer.

24. Collect and Package Physical Evidence
Physical evidence must be collected and packaged correctly so it does not change from the time it was collected to the time it is processed by the crime lab. Changes such as evaporation, contamination, breakage, etc.
Each different piece of physical evidence must be packaged separately.
Evidence must be handled with forceps (gloved hands only) or similar tools

25. Collect and Package Physical Evidence
Plastic pill bottles, manila envelopes, glass bottles: for storing hair, fibers, glass and various small or “trace” evidence.
Paper with “druggist fold”: an alternative way to store trace evidence.
Why must blood-soaked items be stored in paper bags or manila envelopes?
Where should charred items from arson be stored and why?

26. Blood-stained materials must be stored in paper bags or manila envelopes
Blood-soaked clothing must NOT be stored in air-tight containers because the trapped moisture may cause the growth of mildew and mold and destroy the blood.
All clothing in fact, must be air-dried and individually stored in paper bags.
Charred clothing or debris on the contrary, MUST be stored in air-tight containers so that evaporation of volatile petroleum residues does not occur.

29. How do CSIs Maintain Chain of Custody
A list must be maintained of all persons who came into possession of a particular item of evidence.
Failure to do this may will lead to serious questions regarding the authenticity and integrity of the evidence and it may not be admissible in court.
Each time an evidence container is opened and closed, it must be sealed with a label with the examiner’s name, date and location of the item.
If the evidence is moved to another location/lab, the date of this transfer must also appear on the label.
In addition, a complete record of all persons in touch with the evidence is maintained and these persons may be summoned to court to testify during court proceedings.

30. So now that we have the evidence,
what do we do with it?
Think biological evidence: hairs, body fluids, fibers.

31. Obtain Standard/Reference Samples
All evidence must be compared to with a known (standard/reference) sample
For example, blood-stained evidence must be accompanied by blood or buccal samples from both the victim as well as the suspect(s)
Same is true with hair, fibers, soil, etc.
Buccal= oral (of the mouth)

32. Submit Evidence to Lab
Can be delivered to lab by personal delivery or mail delivery but certain materials cannot be mailed – explosive, certain chemicals, live ammunition, etc.
Receiving lab must get a case history or any such report along with the evidence.
There should be a clear request of type of examination for each piece of evidence – however, an analyst may perform other tests on the pieces of evidence if necessary (in addition to the tests requested)
An evidence submission form must be completed with a list of all evidence items being submitted for tests.

33. CSI Clean-up crew