FORENSIC SCIENCE

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FORENSIC SCIENCE

• The Crime Scene Team

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Complex ReasoningIn Forensic Science

• Members of the CSI Team must employ the following
  skills
• Deductive reasoning
• Communication
• Logic
• Observation
• Patience
• Methodical Approach

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How are your deductive reasoning skills?

• When Mrs. Jackson came back from lunch, there
  were several messages on her desk. By changing
  each digit of the phone numbers to one of the
  three corresponding letters on the telephone
  buttons, can you determine her relationship to
  each caller?
• (Answers are on the next slide)

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Deductive Reasoning Answers

• 336-8478 dentist
• [phone] accountant
• 774-6837 printer
• 487-2263 husband
• 247-5463 airline
• 832-2437 teacher

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CORPUS DELICTI

• Corpus delicti (body of the crime) is a legal
  term that refers to the principle that proof of a
  crime must occur before a person can be convicted
  of the crime.
• Therefore the CSI team must prove
• that a crime occurred
• that the person charged with the crime was
  responsible for the crime
• Sources of Evidence needed for proof
• Body/Victim(s)
• Primary and/or Secondary Crime Scene
• Suspect(s)

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Crime Scene Team

• The CSI Team is a group of professional
  investigators, each trained in a variety of
  special disciplines.
• Team Members
• First Police Officer on the scene
• Medics (if necessary)
• Lead Investigator
• Medical Examiner (if necessary)
• Photographer
• Field Evidence Technician
• Note Taker
• Sketch Artist

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Crime Scene Team (cont)

• Although they do not actually work at the crime
  scene, the laboratory technicians analyze the
  evidence and provide answers to the
  investigators.
• The Lab Team includes
• pathologist serologist
• DNA expert toxicologist
• forensic odontologist forensic anthropologist
• forensic psychologist forensic entomologist
• firearm examiner bomb and arson expert
• Document/handwriting experts fingerprint expert

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The Role of Each Team Member

• Each member of the team has a very specific job
  that occurs in a specific time frame. For
  example, the evidence technician cannot collect
  the evidence until the photographer has finished
  taking pictures and the sketch artist has
  completed a rough draft. This is an established
  protocol that must be followed at every crime
  scene.

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The Protocol

• A crime or suspected death has occurred, a
  telephone call has been placed to 911 and the
  police are dispatched to the scene.
• Listen to real 911 calls
• http//www.911callers.com/
• The First Officer at the Scene is the lead crime
  scene member. The acronym ADAPT explains his/her
  role.

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First Officer at the Scene

• A Assess the crime scene
• D Detain any witnesses
• A Arrest the perpetrator
• P Protect the crime scene
• T Take notes

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ADAPT

1. The First Officer on the Scene will assess the
   scene to determine if the scene is safe, if there
   is a victim that needs assistance and identify
   all escape routes. Medics will be called if
   needed.
2. Next, the officer will instruct potential
   witnesses to remain at the scene.
3. Arrests will be made if warranted.
4. The officer will secure the scene with crime
   scene tape.
5. After the scene is secure, the officer will
   monitor the entrance and begin security log notes.

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The Lead Investigator

• The lead investigator will be the first member to
  work the scene. He/she has a limited amount of
  time to observe the scene in an untouched state.
• The lead investigator determines the boundaries
  of the crime scene, identifies any
  entrances/exits and completes an initial
  walk-through to gain an overview of the situation
  and a plan for examining and documenting the
  scene.

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Primary vs. Secondary Crime Scenes

• The Lead Investigator may soon realize that there
  are other locations related to the crime scene
  under investigation. These locations would be
  secondary scenes.
• A primary crime scene is the location where the
  offense occurred. Secondary scenes are any
  locations that are related and may provide
  evidence.
• For example, in a bank robbery, the bank is the
  primary crime scene. The getaway car and
  apartment where the robbery plans were finalized
  are secondary scenes.

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An Investigators Job According to Dr. Lee

• The wise forensic investigator will always
  remember that he must bring all of his life
  experiences and logic to find the truth. This
  means common sense, informed intuition, and the
  courage to see things as they are. Then he must
  speak honestly about what it adds up to.
• Dr. Henry Lee
• Chief Emeritus for Scientific Services and the
  former Commissioner of Public Safety for the
  state of Connecticut

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Crime Scene Search Patterns
The Lead Investigator will determine will type of
search pattern to implement. There are four main
patterns.

• Spiral

• Grid

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Crime Scene Search Patterns (cont)

• Strip or Line

• Quadrant or Zone

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An Outdoor Crime Scene

• Many times a crime scene is located outside.
  While the roles of the crime scene team remain
  the same, the search patterns are markedly
  different.
• An outdoor crime scene is mapped. The mapping
  style depends on the scene.

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Crime Scene Mapping(outdoors)

• Azimuth--uses a compass beam to determine the
  location of each piece of evidence
• Triangulation--uses two points at the crime scene
  to map each piece of evidence
• Coordinate or grid--divides the crime scene into
  squares for mapping.
• Suspended Polar Coordinate--for use in mapping
  evidence in a hole
• Baseline--set a north/south line and measures
  each piece of evidence from this line.

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Photographer

• Once the lead investigator has completed an
  overview of the scene, the photographer will
  enter the scene.
• The photographer will begin taking wide view
  photographs of the scene.

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Photographer (cont)

• After the Evidence Technicians have identified
  and numbered the evidence, the photographer will
  take close photographs of each piece of evidence.
• These photographs must include a ruler to provide
  a reference to size.

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Evidence Technicians

• The technicians will begin a through, methodical
  search for evidence using the search pattern
  determined by the lead investigator.
• Physical evidence may be anything from large
  objects to microscopic traces. Therefore, it is
  important to collect objects that may carry trace
  evidence.
• All evidence must be collected, packaged and
  labeled according to established protocol.

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Chain of Custody

• The evidence technicians must maintain the chain
  of custody.
• This is a chronological documentation of each
  piece of evidence.
• If the chain of custody is not maintained then
  the court case is compromised.

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Contamination

• In addition to maintaining the chain of custody,
  each team member has to take precautions to not
  contaminate the evidence.
• Wearing gloves is the most important precaution.

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The Sketch Artist

• Once photographs have been taken, the sketch
  artist must complete a rough sketch.
• The rough sketch must include
• A compass heading that indicates North
• A Legend for all objects in the sketch
• Correct Measurements
• Points of entry/exit
• Date, time and location

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Crime Scene Sketch Example (Rough)
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The Final Sketch

• The sketch artist will use the rough sketch as a
  guide when creating the final sketch.
• All items on the rough sketch must be included on
  the final sketch.
• The final sketch should be drawn to scale using
  graph paper or a computer.

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Crime Scene Sketch Example (Final)
Date August 14, 2001 Criminologist Ann
Wilson Time 1135 a.m. Location 4358
Rockledge Dr St. Louis, Mo.
A. Couch/sofa B. Female body C. Knife D. Over
turned Lamp E. Chairs F. Table G. Fireplace
E
c
B
D
G
A
E
E
E
E
F
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The Sketch Artist (cont)

• If any eye witnesses can give a description of
  the suspect(s), the sketch artist will create a
  composite sketch. This composite may be hand
  drawn or computer generated.
• Of course, the sketch is only as good as the
  information from the eye witness.
• How reliable is an eye witness?

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Reliability of Eyewitness

• Factors
• The nature of the offense and the situation in
  which the crime is observed.
• The characteristics of the witness.
• The manner in which the information is retrieved.
• Additional factors
• The witnesss prior relationship with the
  accused.
• The length of time between the offense and the
  identification.

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A TRUE EYEWITNESSCrazy Criminal

• As a female shopper exited a New York
  convenience store, a man grabbed her purse and
  ran. The clerk called 911 immediately and the
  woman was able to give them a detailed
  description of the snatcher. Within minutes, the
  police had apprehended him. They put him in the
  car and drove back to the store. The thief was
  then taken out of the car and told to stand there
  for a positive ID. With that he replied, Yes,
  Officer. . Thats her. Thats the lady I stole
  the purse from.

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The Sketch Artist (cont)

• When skeletal remains are found and the identity
  is unknown, the artist may recreate an image
  through facial reconstruction.
• This is a 3-Dimensional Technique where clay is
  applied directly to the skull following contours
  and tissue depth markers.
• Often the artist has to make an educated guess in
  regards to the hair and eyes.

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Case Solved Due to Facial Reconstruction
The Skull The Model Case
Solved
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The Note Taker

• Notes must be taken throughout the processing of
  the crime scene.
• The notes must include
• A detailed description of the scene and evidence.
• The time, method and technician that discovered
  and collected any piece of evidence.
• The names, reasons and times for anyone that
  enters the crime scene.
• Notes may be handwritten, tape-recorded or
  video-recorded.

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The Medical Examiner

• The Medical Examiner will be called when there is
  a corpse.
• Any evidence on the corpse and the corpse itself
  is property of the M.E.s office.
• The M.E. will take photographs and temperatures
  at the scene.
• The corpse will be bagged and the rest of the
  investigation will occur at the M.E.s office.

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A Lost Corpse

• Occasionally the evidence indicates that there
  should be a corpse yet none is located at the
  scene.
• A different approach is needed in this
  circumstance.

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Cadaver Dogs

• Dogs, with a sense of smell 100 times better
  than humans, can sometimes find what would be
  overlooked. They are specially trained to locate
  injured, lost and/or deceased individuals. They
  are trained as air-scent dogs or article (cloth)
  scent dogs.

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Cadaver Dogs

• Dogs are trained to locate human body
  fluids including blood, hair, teeth, urine, and
  semen. The dog on the left in a training
  exercise is trying to locate clothing with blood.
  Her name is Cinder.

www.moregionck9search-rescue.com
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Cadaver Dogs
Looking at a crime scene, humans would probably
miss something as small as this tooth. The dog
found it within minutes of searching the scene.
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After the Scene has been Processed

• The evidence is delivered to the team members at
  the crime lab.
• These forensic scientists will examine and
  analyze each piece of evidence.
• Their findings/results will dictate how the
  investigates continues.

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Investigative FlowChart
Why Did It Happened?
Who Did It?
What Happened?
Crime Scene Evidence Collection Witness,
Suspect and Motive Development
Investigative Stage Profiling Means
Motive Opportunity
Identification and Arrest of Suspect


Post Scene Evidence Processing Cause,
manner, time of death
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Just A Thought

• Its not what you know that hurts you, its what
  you think you know and its not so . .
  . . .Mark Twain
• How does this apply to forensic science and crime
  investigations?