Processing the Crime Scene

Processing the Crime Scene

• First responders job:– SAFETY first (scene and victims)– Secure the scene

• People, press• Don’t move body w/o consent of coroner• Keep witnesses separate

• Gloves, goggles, shoe covers

• No eating, drinking

Are all crime scenes processed the same way?

No, major work ups are done only for

a) severe crimes

b) big-time burglaries

• Primary crime scene: site of crime– Ex. Murder scene

• Secondary crime scene: related to the primary scene– Ex. Site where body is dumped– Ex. Suspect’s house

Processing the Scene

• 1. Preliminary walk-through (survey)• 2. Documentation• 3. Proper collection (detailed search)• 4. Packaging• 5. Preservation• 6. Scene reconstruction

Survey

• Be curious• Be skeptical

Identify the scope of the crime-scene and possible locations for evidence.

Be curious!

Murder / Burglary?

Murder or Suicide?

Insurance Fraud?

Arson to cover another crime?

Documentation

Photos

Sketches

Notes

Video

Photos

• Start from wide-angle view and move in

• # all evidence

• Picture with ruler/picture w/o ruler

• Video used but should not be narrated or edited

Sketches

• Rough sketch at scene

• Final sketch later

• Perspectives for sketches– A. Overhead (bird’s eye)– B. Elevation (side view)

Sketches

• Use at least 2 fixed points for each object

• Forensic surveyor may create 3-D models

• GPS may be used at large scenes

Notes

• Be VERY detailed.

• Need to make sense years later

Video

• Do not add sound

• Do not edit

• Low resolution compared to a camera

• Do not interrupt once you have started taping.

• General --> specific

Proper Search/Collection

• Daylight better than artificial light

• Oblique lighting – from an angle

Type of search

• Line or strip

• Grid

• Zone

• Wheel, ray

• Spiral

Packaging

• Package fragile first (fingerprints)

• Send whole articles of clothing

• Bloodstains• A. scrape• B. transfer to wet swab• C. cut out

Packaging

• Forceps, pill bottles, envelopes, vials

• Druggist fold

• Do NOT put bloodstains in airtight cont.

• DO put charred fire debris in airtight container.

Controls

Known standards for comparison to evidence

Examples of Controls

• Ex. Control paint from suspect vehicle in hit and run

• Ex. Control hair from victim/suspect • Ex. Control…Blood or cheek swab from

victim/suspect• Ex. Control (Unburned) samples of wood or

carpet

Packaging

• Submit to lab for testing• Personal delivery• Mail

Preservation

• Secure area

• Chain of custody

Chain of Custody

• Record of who handles the evidence– Case #– Description– Initials– Date– Time– Location– Evidence #

Scene Reconstruction

• Hypothesize the likely sequence of events using:

• Shoeprints• Fingerprints• Tool marks• Blood• Bullet trajectories• Body