Warm-Up

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Warm-Up
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Crime Scene Investigation
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Crime Scene Team

• A group of professional investigators, each
  trained in a variety of special disciplines.
• Team Members
• First Police Officer on the scene
• Medics (if necessary)
• Investigator(s)
• Medical Examiner or Representative (if necessary,
  also called Coroner)
• Photographer and/or Field Evidence Technician
• Lab Experts
• pathologist serologist
• DNA expert toxicologist
• forensic odontologist forensic anthropologist
• forensic psychologist forensic entomologist
• firearm examiner bomb and arson expert
• document and handwriting experts fingerprint
  expert

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Crime Personnel
POLICE OFFICERS are typically the first to arrive
at a crime scene. They are responsible for
securing the scene so no evidence is destroyed
and detaining persons of interest in the
crime. The CSI UNIT documents the crime scene in
detail and collects any physical evidence. The
DISTRICT ATTORNEY may be present to help
determine if any search warrants are required to
proceed and obtains those warrants from a judge.
The MEDICAL EXAMINER/CORONER (if a homicide)
may or may not be present to determine a
preliminary cause of death. SPECIALISTS
(forensic entomologists, anthropologists, or
psychologists) may be called in if the evidence
requires expert analysis. DETECTIVES interview
witnesses and consult with the CSI unit. They
investigate the crime by following leads provided
by witnesses and physical evidence.
Source http//science.howstuffworks.com/csi.htm
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7 Ss of Crime Scene Investigation

• 1. Securing the Scene
• Responsibility of the first responder
• Safety of everyone in vicinity is top priority
• Evidence preservation is second priority
• 2. Separating the Witnesses
• Avoids collusion (making a story match)
• Questions that should be asked include

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Secure the Crime Scene
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Questions for Witnesses

• 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 crime
  scene?

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3. Scanning the Scene

• Determine if it is a primary or secondary scene
• Primary crime scene The original location of a
  crime or accident.
• Secondary crime scene An alternate location
  where additional evidence may be found.
• Where should photos be taken?
• Wear protective gear to prevent
• contamination of crime scene.

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4. Seeing the Scene

• CSIs need to see the scene
• Photos with and w/out rulers should be taken
• Triangulation of stationary objects should be
  included for reference points

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Photographing the Scene

• Take at least 3 shots
• Midrange shot show how the item is related to
  its surroundings
• Close-up bring out details of item
• Take 2 close-up shots if marking or measuring
  device is used
• One shot without device, one shot with device

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Mark Evidence with Tents
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5. Sketching the Scene

• Position of body (if any) and any other evidence
• Should be measured from 2 immovable landmarks
• North should be labeled and a scale should be
  provided
• Positions of furniture, doors (inside), shrubs,
  trees (outside) should be included

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• 6. Searching for Evidence
• Spiral, grid, linear or quadrant patterns should
  be used
• 7. Securing and Collecting Evidence
• Physical evidence must be packaged and collected
  before time and weather can alter it
• The Golden Hour the window of opportunity to
  collect time-sensitive information or evidence

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Packaging Evidence

• Bindle or Drugests Fold folded paper used to
  hold trace evidence

1. Crease a clean paper and place the evidence in
   the X position (as shown above).
2. Fold in the left and right sides, and then fold
   in the top and bottom.
3. Put the bindle into a plastic or paper evidence
   bag affixing a seal over the opening.
4. Write your name on the seal.

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Packaging Evidence

• Proper packaging, sealing and labeling is vital
• Liquid/Arson remains - airtight/unbreakable
  containers
• Biological evidence - breathable containers so it
  can dry out
• Dry item - bindle ? plastic or paper container
• Must include a evidence log and chain of custody

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Chain of Custody

• Essential to maintain in order to present
  credible evidence in court, a chain of custody
  log is essential.
• Original collector bags evidence properly,
  labels it properly, seals it and signs the sealed
  edge.
• Next person to receive evidence signs that they
  received it (lab technician for example) lab
  tech opens sealed container at a location other
  than the sealed edge after examination, tech
  repackages , signs log and reseals with new
  tape/signature.

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Labeling Evidence for Chain of Custody

• Containers should be sealed with tamper proof
  tape, and dated and initialed
• Each package should contain
• Date, time, and location
• Case number
• Agency and collectors name
• Victims name(s)
• Description of contents
• Never package two items from two different
  sources or locations

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Evidence Label

• Indicates every person who has handled the
  evidence
• Log must be attached to evidence packaging

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Evidence Log

• Case number
• Item inventory number
• Description of evidence
• Name of suspect
• Name of victim
• Date/time of recovery
• Signature of person
• recovering the evidence
• Signature of any witnesses present during
  collection

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Evidence Analysis

• Done in forensic labs the largest is the FBI
  crime lab
• Forensic lab technicians are specialists unlike
  what you see on tv
• Results sent to lead detective who then attempts
  to reconstruct the crime scene

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Investigating the Evidence
Drug Chemistry Determines the presence of
controlled substances and the identification of
marijuana Trace Chemistry - Identification and
comparison of materials from fires, explosions,
paints, and glass. Microscopy Microscopic
identification and comparison of evidence, such
as hairs, fibers, woods, soils, building
materials, insulation and other
materials. Biology/DNA Analysis of body fluids
and dried stains such as blood, semen, and
saliva. Toxicology Tests body fluids and
tissues to determine the presence of drugs and
poisons. Latent Prints - Identification and
comparison of fingerprints or other hidden
impressions from sources like feet, shoes, ears,
lips or the tread on vehicle tires. Ballistics
(Firearms) Study of bullets and ammunition
through the comparison of fired bullets,
cartridges, guns, and gunpowder patterns on
people and objects. Toolmarks Examines marks
left by tools on objects at a crime scene or on a
victim, such as a hammer used to break a door or
a screwdriver used to pick a lock. Questioned
Documents - Examination of documents to compare
handwriting, ink, paper, writing instruments,
printers, and other characteristics that would
help to identify its origin.
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What evidence would you collect and how?