Crime Scene Investigation

Crime Scene Investigation

The 7 Ss of Crime Scene Investigation 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 Locards exchange principle contact between individuals and locations leads to an exchange of trace evidence First officer on scene responsibilities (check list handout): Secure safety of individuals at the scene 2. Approach scene cautiously (look, listen, smell) 3. Obtain medical attention for anyone injured 4. Call in backup help, including medical and CSU personnel 5. Separate witnesses

6. Perform initial walk-through (scan the scene) 7. Search scene briefly to notify lab of equipment needed 8. Collect information, including address/location of the scene, time date, type of call, names and addresses of all parties involved and present 9. Securing integrity of the scene by establishing boundaries of the scene and setting tape around parameter 10. Protect crime scene by remaining alert and attentive 11. Document the entry and exit of all authorized by keeping a security log 12. Provide brief update to the next-of-command officer to arrive on scene 1. 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 area 2. Close-up photos with and without measuring ruler 3. Photos of triangulation of stationary objects 4. 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 evidence Sketch should include: 1. Objects measured from 2 immovable landmarks 2. North should be labeled 3. Scale of distance should be provided 4. 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 used Should include: North Scale

Case # Date Location Name of officer/investigator Searching for evidence should be systematic Types of searches: 1. Spiral

2. Grid 3. Linear 4. Quadrant or zone The type of search depends on: 1. Area of the crime scene 2. number of investigators present The location of evidence should be: 1. Marked 2. Photographed 3. 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 (druggists 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 evidence 4. Name of suspect 5. Name of victim 6. Date and time of recovery 7. Signature of person recovering evidence 8. Signature of any witness present during collection Packaging Evidence: 1. Choose appropriate-size sheet of clean paper

for bindle 2. Crease paper into portions/partition size depends on evidence size 3. Place evidence in a central location on paper Evidence Fold paper left and right sides in 5. Fold in top and bottom 6. Insert the top flap into the bottom flap 7. Tape-close 8. Place bindle inside a plastic or paper bag

9. Fold bag closed 10. Place a seal over the folded edge of evidence bag 11. Have collector write his/her name across folded edge 4. 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 Collectors 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

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