First responding officer – it is his/her duty to secure the scene by limiting access to the scene and preserve scene with minimal contamination
1st priority – secure safety of all individuals in the scene by limiting access to it 2nd priority –preservation of evidence Locard’s exchange principle – contact between individuals and locations leads to an exchange of trace evidence
First officer on scene responsibilities (check list handout): 1. Secure safety of individuals at the scene2. Approach scene cautiously (look, listen, smell)3. Obtain medical attention for anyone injured4. Call in backup help, including medical and CSU personnel5. Separate witnesses6. Perform initial walk-through (scan the scene)7. Search scene briefly to notify lab of equipment needed8. Collect information, including address/location of the scene, time date, type
of call, names and addresses of all parties involved and present9. Securing integrity of the scene by establishing boundaries of the scene and
setting tape around parameter10. Protect crime scene by remaining alert and attentive11. Document the entry and exit of all authorized by keeping a security log12. Provide brief update to the next-of-command officer to arrive on scene
3rd priority – witnesses must not be allowed to talk to each other to avoid collusion (creation of story by witnesses talking to each other)Questions to ask:When did crime occur?Who called in the crime?Who is the victim?Can the perpetrator be identified?What did you see happen?Where were you when you observed the crime
scene?
Scan the scene to a. determine where to take photos b. determine primary crime scene c. determine secondary crime scene ( if this applies to the case)
Examiner needs:1. Photos of overall area2. Close-up photos with and without
measuring ruler 3. Photos of triangulation of stationary objects4. Photos taken from different angles and
distances 5. Several close-up photos of any evidence
and body(/ies)
A rough sketch of the scene is made noting – position of body (if any) any other evidenceSketch should include:1. Objects measured from 2 immovable landmarks2. North should be labeled3. Scale of distance should be provided4. Objects in the vicinity of the scene should be
included Indoors: doors, windows, furniture, etc Outdoors: trees, vehicles, hedges, etc
Final Sketch – done later more accurate copy used in court proceeding computer programs can be usedShould include: North Scale Case # Date Location Name of officer/investigator
Searching for evidence should be systematic Types of searches:
1. Spiral 2. Grid3. Linear4. Quadrant or zone
The type of search depends on:1. Area of the crime scene2. number of investigators present
The location of evidence should be:1. Marked2. Photographed3. Sketched
Evidence needs to be – properly packaged sealed labeled
Liquids and arson – stored in airtight unbreakable containers Biological evidence – stored in breathable containers for evidence to dry out to reduce mold growth
Biological evidence – a. Needs to dry out in breathable container b. Is stored in paper bindle (druggist’s fold) c. Placed in plastic or paper container d. Is later sealed w/tape e. Collector signs his/her name across the tape
An evidence log and chain of custody document must be attached to the evidence container
Evidence log should contain:1. Case #2. Item inventory #3. Description of evidence4. Name of suspect5. Name of victim6. Date and time of recovery7. Signature of person recovering evidence8. Signature of any witness present during collection
Packaging Evidence:1. Choose appropriate-size sheet of clean paper
for bindle2. Crease paper into portions/partition size
depends on evidence size3. Place evidence in a central location on paper
Evidence
4. Fold paper left and right sides in5. Fold in top and bottom6. Insert the top flap into the bottom flap7. Tape-close8. Place bindle inside a plastic or paper bag9. Fold bag closed 10. Place a seal over the folded edge of
evidence bag11. Have collector write his/her name across
folded edge
Wet evidence should never be packaged in plastic container
DNA will degenerate Evidence may become moldy, thus useless Control samples must also be obtained from
victim for exclusion
Essential in securing the evidence:
Individual who finds evidence marks it for id and bags it Final container for evidence is a collection bag which is
labeled and then sealed Collector’s signature is written across sealed edge Container is given to next person responsible for its care That person takes it to the lab and signs it over to the
technician Technician opens package for examination After examination, technician repackages evidence
within its original packaging Technician reseals evidence in a new packaging Technician seals, signs name across label seal Technician signs the chain of custody log attached to the
packaging