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Criminalistics The Crime Scene. Information from Crime Scene & Physical Evidence Corpus Delecti- facts that establish crime occurred Modus Operandi- perpetrator’s.

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Presentation on theme: "Criminalistics The Crime Scene. Information from Crime Scene & Physical Evidence Corpus Delecti- facts that establish crime occurred Modus Operandi- perpetrator’s."— Presentation transcript:

1 Criminalistics The Crime Scene

2 Information from Crime Scene & Physical Evidence Corpus Delecti- facts that establish crime occurred Modus Operandi- perpetrator’s “signature” Link person to person, object, scene Prove/disprove witness, victim, suspect statements ID of suspect- AFIS, CODIS databases Investigative leads- paint, footwear Reconstruction- “How it happened”

3 WHO RESPONDS TO THE SCENE Detectives Investigating Case Crime Scene Unit Evidence Search & Processing Identification Unit Photography & Fingerprints Medical Examiner Homicides, Suspicious Deaths

4 Crime Scene Procedures 1. Protect scene 2. Search for physical evidence 3. Document scene- Notes, photos, measurements, sketch 4. Collect & preserve evidence 5. Transport to laboratory 6. Analyze evidence & reconstruct scene

5 SECURING THE SCENE  Barrier Tape - or other means (vehicles)  Secure all routes of access into scene  Log Book  Restrict entry

6 Crime Scene Safety Wear protective clothing and gear Always use latex or nitrile gloves Be alert to sharp objects: Knives, syringes, glass, etc. Don’t reach where you can’t see!!! Don’t eat, drink, spit or smoke within the scene Universal Precautions – body fluids n Bleach or dispose of equipment contaminated with blood

7 Supplemental Resources  K-9 Unit  Metal Detectors  Aviation/ Marine Bureau  Emergency Services  Lighting  Halogens  Alternate Light Source/ UV

8 EVALUATING THE SCENE n Walk Through One member of each group Determine safe areas to walk Identify important aspects of the scene Develop a plan of action, initial theory

9 SCENE DOCUMENTATION - 1 n Video Photography – 3D Orientation Introduction- placard or audio Start outside scene Walk through scene Overall then close-up on important items Continuous taping; no sound, no editing

10 SCENE DOCUMENTATION - 2 n Still Photography Work from outside to inside Overall, midrange, then close-ups (with & without ID tag) Examination Quality Photos of Impression Evidence Overlap photos for perspective/context Document evidence with tags and scale, cones, flags, placards Photo Log: date, time, roll#, exposure, settings, description of item Patterns (“roadmap” w/ references)

11 Evidence Documentation

12 Roadmapping Stain Patterns Photograph overall pattern using a scale of reference

13 Roadmapping Stain Patterns Midrange Close-up

14 SCENE DOCUMENTATION - 3 Crime Scene Notes List Pertinent Information Date, Time, Location Personnel Lighting, Weather Observations-be objective Items Recovered:  Location of items  Photo taken?  Time Collected  Test results, if any

15 SCENE DOCUMENTATION - 4 Rough sketch Before collecting evidence Overhead or side view Compass heading Legend Measurements fm 2 fixed pts. Coordinate Baseline N north east Item

16 1 2 3 RP 1 RP 2 Baseline Method – Outdoor sketch 20 ft 35 ft 60 ft 18 ft 28 ft 20 ft Tape measure 0 ft N

17 RP 1 RP 2 Triangulation Method N #1 100 ft 64 ft 36 ft Item fm RP1 fm RP #1 knife 36’ 64’

18 Total Station

19 SCENE DOCUMENTATION – 4 Finished CAD sketch Homicide Investigation CC# 08-246801 30 Campus Ct, Riverhead RB 02-10-08 Legend 1Cartridge 2Bloodstain 3Cigarette butt 4Ski mask 5Beer can

20 Search Patterns n Line (Strip) Method  Large outdoor scenes  Uneven terrain  Uses several searchers  Move at same pace  Mark evidence when found

21 Search Patterns n Grid Method Move back and forth in parallel lines When the area has been covered, switch to perpendicular direction Each area viewed twice, different perspective

22 Search Patterns n Quadrant/Zone Method Large outdoor scenes Divide scene Diagram quadrants Collect evidence within the quadrant Air crash Rooms in house Automobiles

23 Search Patterns n Spiral Method Indoor scenes Start at perimeter or center Move in circular pattern

24 Locating Physical Evidence Primary Scene- where principal activity occurs ie. body, cartridge casings, ransacked bedroom Target area, natural or forced entry & exit points Secondary Scene- associated locations Vehicle Body dumped Dumpster, garbage cans Staging area Storm drains Perp’s residence Neighbor’s yard Triage processing if evidence may be compromised Try to locate the Primary Scene ASAP !!!

25 Locating Physical Evidence  Ceiling- blood, tissue, projectiles  Drapes- blood, fibers  Trash cans- gloves, weapons  Refrigerator- food  Toilet- hairs, urine, fingerprints,  Missing items- investigative information  Location of PE- may be relevant if suspect was resident or frequented location on previous occasions

26 Locating Physical Evidence: Bodies n Another type of “Scene”  Document with notes and photography  Sexual Assault Kit, fingernail scrapings  Fibers, hairs, dried stains on body  Gunshot residue  Accelerants, other Trace Evidence  Clothing, personal items

27 EVIDENCE COLLECTION Document evidence prior to collection Package each item separately Place evidence in container at scene Prevent loss, alteration, contamination! Mark with identifying #, initials, date Chain of Custody !!!!!!! Secure the evidence at the time of collection

28 Chain of Custody n Authenticates the integrity of the evidence  Who had the evidence ?  When did they have possession of it ? PROVE IT!

29 Security Tape

30 Jane Doe

31 EVIDENCE COLLECTION n Fingerprint Evidence  Do not obliterate prints  Package loosely in boxes  Handle only unprintable areas  Do not package in plastic bags

32 EVIDENCE COLLECTION n Biological Evidence Paper containers only If wet, air dry ASAP Collect item with stain, if possible Scrape into paper fold Collect stains with damp swab

33 EVIDENCE COLLECTION n Firearms Evidence  Assume gun is loaded!  Document location of ammunition in weapon  Package ammunition separately  Make sure that all weapons are clear 1 2 3 4 5 6

34 EVIDENCE COLLECTION n Trace Evidence  Paint - Scrape into paper fold Static can cause loss!  Glass - Package to protect: Evidence - so it doesn’t break Handler - to avoid injury  Knives - Package to contain sharp edges

35 LEGAL ISSUES n Search Warrant not required  Search of premises for suspect or victim  To prevent immediate destruction of evidence  Consent  Upon arrest, search of person

36 Reference Standards/Exemplars n Material from KNOWN source is used for comparison to QUESTIONED evidence Glass Paint Carpet Clothing Buccal swab, blood sample Hair

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