Unit 2- Evidence & Crime Scene
Investigation
CSI
“SPOT it” for Crime Scene
Investigating
1. Secure the Scene
2. Plan
3. Observe (notes/ photos/ sketch)
4. Take
Crime Scene Team
1) Police Officer (1st responding officer)
CSI TEAM
1) Team Lead
2) Photographer
3) Sketcher
4) Evidence Recorder/ Collector
5) Specialists (if needed)
Secure:
Duties of 1st responding Officer:
1) Check safety of scene (control physical threats)
2) Tend to the injured (call ambulance)
3) Separate witnesses and suspects
4) Secure the scene
• Exclude all unauthorized personnel
• Barricade boundary
Plan:
Lead CSI & Team Members:
• Cautiously walk through scene
– Establish safe route through scene (don’t disturb evidence)
– ID points of entry, attack, & exit
• Establish team roles
Observe
• Take photos
• Take notes
• Sketch scene
These help you “see” the scene
months/ years later
How open minded are you?
Can you change your perspective?
The Body Can Lead To An Object
……Sometimes The Object Isn’t A Weapon
Observing Evidence / Movement
Sketches• Used to supplement photos
• What to include:
– Dimensions of rooms, furniture, doors, & windows
– Evidence or things hosting the evidence (ex: table)
– Distances from two set points to the objects/ evidence
in the room
– Date, time, location, investigators names, case
identifier
– Legend/ Key, scale, compass orientation (North is at
top of page)
Rough Sketch
Final Sketch
2D vs. 3D
Types of Measurements
COORDINATE SYSTEM
3 ft.
5 ft.
TRIANGULATION20 ft.
17 ft.
BASELINE
10 ft.
7 ft.
GRID SYSTEM
1
2
3
4
A DB C
Notes• Date
• Time
• Description of location
• Weather
• Environment
• Description of the Scene with location of physical evidence
• Who recovered evidence & how it was packaged
Photograph and Videotape
Photos should include:
• Overall views of Scene
– looking into & out of scene
– Nearby areas
– Points of entry and exit
• Evidence Shots
– Medium range: evidence at
scene
– Close-ups: for details
• Rulers used in close-up photos
if size is important
Correct Photography
Background Photos / The Scene
360° Pictures
Wallet
Medium range shot Close up shot
Search
• Use a search pattern
(grid, line, zone)
• Use alternate light
sources
• Critical areas are checked
for trace evidence (hair,
fibers, bodily fluids,
fingerprints)
Shedding The Right Light Is Crucial
Side Lighting Top Lighting
Different Types Of Light
Fluorescent powder and UV light
Alternate
Light Source
Luminol
Trace Metal DetectionDifferent Metals Yield Different Colors
• brass/copper: purple
• steel/iron: black or dark purple
• aluminum: mottled yellow
• lead: tan or cream-colored
• galvanized iron (tin): bright yellow
• background: pale yellow
Aluminum
Lead
Copper
TMD
Pipe Test
Take Evidence• Wear gloves
• Collect fragile items first
• Package each item in a separate
container (appropriate for item)
with a label
• Obtain standards/ reference
samples for later comparison
• Maintain chain of custody
“Bagging and Tagging” is tough work
General Evidence Packaging Rules
1. Dry moist or wet evidence prior to packaging to prevent mold.
2. Allow for air circulation – USE PAPER
3. No plastic bags, sealed tubes, or jars -unless tissue/ tox samples
- arson evidence (no evaporating).
4. Biological items should be dried and kept in freezer
5. Package items separately.
6. Minimal handling - avoid talking/coughing over evidence.
Bagging & Tagging of Evidence
1) Tape seal package with initials before
leaving scene.
2) What goes on the evidence bag:
• type of case
• date
• location of collection
• item description
• police case number or identifier
• serial number or garment identifier
• collector's name and identifier information
• where item is being routed to for analysis
Package All Evidence In
envelopes, paper bags, or cardboard boxes
Guns
• Make safe
• Cartridges and cartridge casings
Ingenious packaging
More good packaging
Bad packaging…
Packaging the EvidenceOH NO,!!! Plastic
with wet material.
Chain of Custody- written record of
who has possession of evidence at all times.Starts with the CSI Evidence Storage Lab Attorney’s?
4 Requirements for Evidence to be
Admitted into Court:
1) It must be legally obtained (search warrant)
2) Must be relevant to the crime (material &
probative)
3) Witness must identify the item, identifying it’s
origin
4) Chain of Custody must be demonstrated
(every person that handled must also be
available to testify)
Search WarrantsPublished Casey Anthony search
warrant = a great example of what goes into a search warrant
• Need probable cause
• Need a detailed affidavit explaining why the authorities want to enter the home
• Explains what specific items they are interested in locating & where they want to look
• signature of a judge(http://blogs.discovery.com/criminal_report/files/casey_antho
ny_search_warrant.pdf )
Warrantless Searches
1) Emergent Situations- police may enter a building because
of emergency situation & evidence found can be used
(but they can’t come back again without warrant- Mincey Case)
2) Impending Loss of Evidence- person or situation might
cause evidence to be lost (ex: fire, person flushing drugs down
toilet)
3) Lawful Arrest- when a person is arrested any property in
his/her immediate control (vehicle, house) can be searched.
4) Consented Search- when person gives consent
Evidence
Types of Evidence
Direct Circumstantial (indirect)
Physical Biological
Individualized
Class
1st hand observations-
eyewitnesses, confession,
& videos
Used to imply a fact, but
does not directly prove it
Or
Individual vs. Class EvidenceIndividual Evidence
• Really high probability of being linked to one, unique source
• Ex:– Fingerprints
• 1 x 1060 = probability of 2 people having same fingerprint
– DNA
– Bullets
– Tire/ footwear patterns
– Tool marks
– Broken glass
Class Evidence
• Object has characteristics common to a group of similar objects
• Ex:– Hair
– Fibers
– Blue jeans
• Can increase the probability of class evidence by finding things that can make it unique:– Ex: stains, wear patterns
on jeans
Eyewitness Accounts• Juries heavily influenced by eyewitness
identifications.
• Lots of innocent people convicted b/c of faulty eyewitness accounts.
Some Issues: – types of questions asked by investigator
– type of crime
• Emotional arousal improves memory to a certain point
(Do you remember where you were when 9/11 happened?)
– time frame of questioning after event
– Cross racial identifications difficult
(watch: Eyewitness Testimony from 60 Mins)
4 Requirements for Evidence to be
Admitted into Court:
1) It must be legally obtained (search warrant)
-Even reference samples like DNA
2) Must be relevant to the crime (material &
probative)
3) Witness must identify the item, identifying it’s
origin
4) Chain of Custody must be demonstrated
(every person that handled must also be
available to testify)
Search WarrantsPublished Casey Anthony search
warrant = a great example of what goes into a search warrant
• Need probable cause
• Need a detailed affidavit explaining why the authorities want to enter the home
• Explains what specific items they are interested in locating & where they want to look
• signature of a judge(http://blogs.discovery.com/criminal_report/files/casey_antho
ny_search_warrant.pdf )
Warrantless Searches
1) Emergent Situations- police may enter a building because
of emergency situation & evidence found can be used
(but they can’t come back again without warrant- Mincey Case)
2) Impending Loss of Evidence- person or situation might
cause evidence to be lost (ex: fire, person flushing drugs down
toilet)
3) Lawful Arrest- when a person is arrested any property in
his/her immediate control (vehicle, house) can be searched.
4) Consented Search- when person gives consent
Questions from COURTExamples of questions asked by defense attorney’s:
1. “Why didn’t you collect that?”
2. “Why didn’t you take that photo?”
3. “Did you consider any other suspects?”
4. “Did you collect evidence to only make my client guilty?”
5. “Have you ever made a mistake – did you make one here?”
6. CSI effect
7. “I see that someone other than you collected this item – how can you prove to me that it was collected properly?”
8. “What if……..” scenarios
9. “How can you explain a finding on your report and there is nothing in your field notes to support that finding?”
10. “Are you an expert?”
11. “Why did you collect evidence that wasn’t analyzed?”
12. “Are you a robot for the state?”
13. “How do you know the evidence wasn’t tampered with during storage?”
Every move you make at a crime scene must be able to be explained - remember everything you do is for court and the jury.
Bullets & Fragments
Gopher Holes
Questioned Documents
Alterations & Obliterations
Can you tell what is obliterated?
A Blank Sheet Could Yield All This?
ESDA Film From 4th Sheet
Electrostatic Detection Apparatus
Reveals indented writing. The machine works by applying a charge to
the evidence and an opposite charge to acetate placed on top of the
evidence. The process transfers indented writing to the acetate.
-FBI
Mikrosil
• Cast prints
• Cast bullet holes in drywall
• Cast any impression in another
surface
Dental Stone? SMILE!