UTube – Crime Scene Evidence
A. Crime Scene Investigation goal – to
recognize, document and collect evidence
at the scene of the crime Engage – pg 22
II. Principle of Exchange
A. Trace evidence – a physical transfer of different
materials whenever people come in contact.
*What type of materials might transfer?
1. Pet hair on clothes or rugs
2. Hair on your brush
3. Soil tracked into your house
4. A drop of blood on your t-shirt
5. A facial tissue
6. Paint chips
7. Fiber from clothing
B. Direct evidence – first hand observation such
as eyewitness accounts or video cameras.
C. Circumstantial evidence – indirect evidence
used to imply fact but doesn’t directly prove it.
1. Physical – impressions such as fingerprints,
footprints, shoe prints, tire impressions and
can also include fibers, weapons, bullets
and shell casings
2. Biological – body fluids, hair, plant parts,
and natural fibers.
3. Trace evidence – hair on a brush, fingerprints
on glass, blood drops on a shirt, soil tracked
into a house from shoes and others.
CSI Video Lab
III. Crime Scene Investigation Team see explore pg. 24
A. At the scene
1. Police Officers
2. Crime-scene Investigators – document the
crime scene in detail and collect physical
b. Sketch artists
d. Evidence collectors
3. Medical examiner – determine cause of
4. Detectives – look for leads, interview
witnesses and discuss evidence with crime
5. Specialists – entomologists (insects), forensic
scientists, forensic pathologists
IV. Seven S’s of Crime Scene Investigation
A. Securing the Scene – first responder
1. safety of individuals
2. preservation of evidence
3. security log of all those that enter the scene
4. collects pertinent information
5. requests any additional needs required
Protecting the Crime Scene Article and WS
B. Separating the Witnesses
1. Do not allow them to talk to each other
2. Ask the following questions:
a. When did the crime occur?
b. Who called in the crime?
c. Who is the victim?
d. Can the perpetrator be identified?
e. What did you see happen?
f. Where were you when you observed the
C. Scanning the Scene see pg. 25
1. Primary crime scene
2. Secondary crime scene
CSIBasics Video: Photographing
D. Seeing the Scene
1. photographs of overall area and close-ups
with and with out measuring device taken
2. Triangulation of stationary objects include in
photos as reference points.
3. View of scene from several different angles
4. Close-ups of any evidence and bodies
E. Sketching the Scene
1. Rough sketch – accurate noting the position
of the body (if any) and any other evidence.
2. all objects should be measured form 2
3. North and South labeled and scale of
4. Any other objects in vicinity of crime scene
F. Searching for Evidence
1. Search Patterns
a. Grid pattern – single investigator
b. Spiral – single investigator
c. Linear – group of investigators
d. Quadrant or Zone – multiple Investigators
Utube: What are the techniques used
to gather crime scene evidence?
Crime Scene Processing Article and WS
Crime Scene Sketch
OJ Simpson Article
G. Securing and Collecting Evidence
1. Needs to be properly packaged, sealed and
a. Liquids and arson remains – stored in
airtight, unbreakable containers.
b. Biologicals – stored in breathable
containers - allows it to dry out (mold).
1. paper bindle (druggist’s fold) –
packaged then placed in a plastic or
2. Chain of Custody and evidence log – must be
attached to evidence container.
1. case #
2. item inventory #
3. description of evidence
4. name of suspect
5. name of victim
6. date and time of recovery
7. signature of person recovering
8. signature of
3. Packaging Evidence
a. Choose appropriate
size of clean paper
b. Crease the paper
c. Place evidence in center
d. Fold as shown
e. Place inside plastic or
paper evidence bag, fold
f. place seal over folded edge of evidence
g. Collector signs over folded
4. Chain of Custody
V. Analyze the Evidence
A. Forensic Lab
1. processes all of the evidence – technicians
are specialized and process 1 type of
2. Results sent to lead detective
VI. Crime Scene Reconstruction
A. hypothesis of sequence of events beginning to
B. Evidence is examined and compared with
witnesses’ statements to determine reliability of
C. Determine how evidence fists into overall crime
scenario. Virtual Crime Scene WQ
VII. Staged Crime Scene – evidence doesn’t fit the
testimony of witnesses.
1. Arson – stages fire to cover another crime
2. Suicide/Murder – murder victim is staged to
look like a suicide.
3. Burglary – staged to collect insurance
B. Determination of Staged Scene
1. Treat all death as homicides
2. Do type of wounds found on victim match
3. Could wounds e self-inflicted?
4. Establish profile of victim; interview friends
5. Evaluate behavior of victim before event
6. Evaluate behavior of suspects before event
7. Corroborate statements with evidential fact
8. Reconstruct the event
9. Conduct all forensic examinations to
determine the facts of the case
Crime Scene Investigator - http://www.yourdiscovery.com/crime/csi/
Don’t Touch The Evidence Lab