1. Crime Scene Investigation

2. What is Crime Scene Investigation?
Main goal is to gather evidence that can be used to identify and convict the person(s) responsible for a crime.

3. Who’s at the Scene of a Crime?
Police Officers – first to arrive, secure the scene
CSI Unit – documents & collects evidence
District Attorney – determines if search warrants are necessary, secures warrants from a judge
Medical Examiner – may be present to determine a preliminary cause of death
Specialists – may be called in if evidence requires special analysis
Detectives – interview witnesses and investigate the crime

4. Preserving and Isolating the crime scene
Responsibilities of 1st Officer arriving: 1. obtain medical assistance for anyone in need 2. arrest any perpetrators 3. exclude all unauthorized personnel 4. isolate the area “yellow tape”– do not cross
- destruction or altering of P.E. can occur when a crime scene is not properly secured & documented Secure & Isolate the Crime Scene Responsibilities of 1st Officer arriving: 1. obtain medical assistance for anyone in need 2. arrest any perpetrators 3. exclude all unauthorized personnel 4. isolate the area

5. So, what exactly needs to be done at the scene of a crime?
Crime scene investigator will conduct an initial walk through
(conditional/transient evidence is noted ex: lighting, smells, sounds, temperature of body are noted)
Investigators will interview witnesses, first responders or victim
During the second walk through, the scene is thoroughly documented through drawings, notes, photographs, and digital video.
If there has been a death, the medical examiner should note the body’s condxition and if possible, estimate the time of death.
Law enforecement officers should try to note and record details such as weather conditions, particular odors, whether lights are on or off, any signs of prior activity at the scene, light and visibility.

6. Observing and documenting the scene
Investigators will examine the scene for evidence, identify points of entry and exit.
Good technique is to use oblique lighting.
(beam of flashlight is swept an angle 1 inch of the surface in a semidark area)

7. Notetaking
Most important parts of processing a crime scene. It includes:
detailed written descriptions of crime scene w/ locations of physical evidence including :
time of discovery
who found it
who packaged and marked it
disposition of item after being collected
must be detailed (step by step of investigation) enough to refresh one’s memory months  years after processing
tape or video recording is advantageous but at some point it must be transcribed
Notes
is a constant activity when processing C.S. and must include:
detailed written descriptions of C.S. w/ locations of P.E. including also:
time of discover
who found it
who packaged and marked it
disposition of item after being collected
must be detailed enough to refresh one’s memory months  years after processing
tape or video recording is advantageous but at some point it must be transcribed

8. Photographs and Videotape
Photos can capture details that even the most observant investigators may miss.
Photographs should be taken before touching or moving any evidence.
All photos should include a ruler for scale

9. Sketches
    Once photos have been taken, the crime-scene investigator sketches the scene
    * Sketch has essential info & measurements at a crime scene.
-- sketch is drawn at the crime scene.
-- shows dimensions & location of objects.
 all sketches should include date and time, scale, reference points, distance measurements, the names of investigators, victims, suspects and legends.  
SKETHCHES
·       Once photos have been taken, the crime-scene investigator sketches the scene
·       Rough Sketch-a draft representation of all essential info & measurements at a crime scene. This sketch is drawn at the crime scene. It shows dimensions & location of objects. Figs 2-4 & 2-5 pp. 47 & 48
·       On the sketch, North should be labeled.
·       Objects r located in the sketch by distance measurements from 2 fixed points. All measurements r made w/ a tape measure.
·       The simplest way to designate an item is to assign it a # or letter. A legend must be placed below the sketch.
Finished Sketch-a precise rendering of the crime scene, drawn to scale.

10. Searching for Evidence
Typical examples of crime scene search patterns are:
1. Line search: used in large open areas
2. Grid: double line search
3. Zone method: effective in houses or buildings. Teams are assigned rooms or small zones to search
The search pattern selected at a crime scene depends on the size & locale of the scene & the # of collectors participating in the search.
Typical examples of crime scene search patterns

11. Search for evidence
4. Wheel or ray: best in small areas. Officers begin at the center and move outward in a pattern that makes a circle
5. Spiral method: best used in areas where there are no barriers or wall. Officers move inward or outward

12. Crime Scene Search Patterns
SPIRAL
GRID
                                      
                                      
                                      
LINEAR

13. So, what exactly needs to be done at the scene of a crime?
There are several different methods of search patterns used during the examination of the scene.

14. Collecting and packaging evidence
Each different item must be placed in separate containers to prevent contamination.
plastic pill bottles, vials, manila envelopes and plastic bags are excellent for collecting evidence.
The most fragile items (fingerprints, bloodstains, and other trace evidence must be collected first)

15. Collecting Evidence 1. Evidence can be massive to microscopic
2. may only be detected in a crime lab
ex. traces of blood on clothing, hair and fibers from vacuum sweeps
3. it is sometimes necessary to confiscate clothing from victim and perp
Critical areas should be vacuumed; sweepings from different areas must be kept separate
5. finger nail scrapings must also be taken from suspects and victims
1. can be massive to microscopic
2. may only be detected in a crime lab
ex. traces of blood on clothing, hair and fibers from vacuum sweeps
3. it is sometimes necessary to confiscate clothing from victim and perp
4. Critical areas should be vacuumed
sweepings from different areas must be kept separate (fig. 2-8 pg 52)
5. finger nail scrapings must also be taken from suspects and victims

16. Collecting Evidence 7. Bloodstains scraped if dry
6. Trace evidence should be left on object unless it is attached to a large object; remove w/ forceps
7. Bloodstains
scraped if dry
transferred to moistened swab
cut out the area of object
8. Each item must be kept separately
9. Trace evidence should be left on object unless it is attached to a large object
remove w/ forceps
Bloodstains
scraped if dry
transferred to moistened swab
cut out the area of object
10. Each item must be kept separately

17. Packaging Evidence Special consideration:
Wet evidence should NEVER be packaged in plastic containers while wet.
   Bloodstained materials should NOT be stored in airtight containers b/c accumulation of moisture may encourage the growth of mold; in these instances wrapping paper, manila envelopes or brown paper bags are used.
  All items of clothing must be air dried & place in individual separate bags.
Charred debris recovered from a fire must be sealed in airtight containers to prevent evaporation of volatile petroleum residue. (new paint cans or tightly sealed jars)
·       Manila envelopes, sealable plastic bags can be used for some evid
·       Bloodstained materials should NOT be stored in airtight containers b/c accumulation of moisture may encourage the growth of mold; in these instances wrapping paper, manila envelopes or brown paper bags r used.
·       All items of clothing must be air dries & place in individual separate bags
Charred debris recovered from a fire must be sealed in airtight containers to prevent evaporation of volatile petroleum residue. (new paint cans or tightly sealed jars)

18. Collecting Evidence All evidence needs to be properly packaged,
sealed and labeled.
The evidence log should contain all pertinent information including:
Case #
Item inventory #
Description of the evidence
Name of suspect
Name of victim
Date & time of recovery
Signature of person recovering the evidence
Signature of any witnesses present
All evidence needs to be properly packaged, sealed and labeled.

19. Chain of Custody
An evidence log and a chain of custody document must be attached to every evidence container.
*Chain of Custody the documented and unbroken transfer of evidence; list of all people who came into possession of an item of evidence (continuity of possession)
An evidence log and a chain of custody document must be attached to the evidence container.
*Chain of Custodythe documented and unbroken transfer of evidence

20. Chain of Custody
Seal the evidence & the collector’s signature is written across the sealed edge.
When the package is reopened at the lab it is opened at a location other than the sealed edge. Every time opened: new seal, new signature, place in new evidence bag.
CHAIN OF CUSTODYlist of people who came into possession of an item of evidence (continuity of possession)
·       every person who handles evid must be accouted for
·       all items must be carefully packaged & marked upon their retrieval at the scene.
·       Record to show collector’s initials, location of evid, & date of collection. Seal evidence & the collector’s signature is written across the sealed edge.
When the package is reopened at the lab it is opened at a location other than the sealed edge. Every time opened: new seal, new signature, place in new evidence bag.

21. So, what happens after the evidence is collected?
Once the crime lab has processed the evidence, the results are forwarded to the lead detective on the case.
It is up to the lead detective and his team to reconstruct the crime scene based upon the evidence and lab findings and determine who committed the crime.
Once a case is made, the person who committed the crime can be arrested and tried in a court of law.

22. How has careful review of a crime scene helped to convict a criminal?
A double murder – no fingerprints, no DNA, no murder weapon. The only thing that could link the killers to the crime were the fibers from the blankets.

23. Quick Review of evidence
*Physical Evidence- any object(s) that can prove that a crime has been committed or can link a crime & its victim or its perpetrator.
Physical Evidence-encompasses any & all objects that can establish that a crime has been committed or can link a crime & its victim or its perpetrator.

24. Physical evidence includes fingerprints footprints shoe prints
tire impressions
tool marks
fibers
weapons
bullets
and shell casings.
Physical evidence includes impressions such as fingerprints, footprints, shoe prints, tire impressions, tool marks. It also includes fibers, weapons, bullets, and shell casings.
Biological evidence includes body fluids, hair, plant parts, natural fibers.

25. Biological evidence includes
body fluids
hair
plant parts
natural fibers.

26. Class Evidence Examples
Single layered paint
Soil
Hairs
Fibers

27. Individualize Evidence
Fingerprints
Handwriting
Bullets (striations)
Toolmarks (striations)
Shoeprints (wear patterns)
Tire prints
Glass fragments that can be matched

28. *Trace evidence small but measurable amounts of physical or biological material found at a crime scene.
Whenever two peope come in contact wi

29. What evidence would you collect?
Mock Crime Scene: