FORENSIC SCIENCE

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FORENSIC SCIENCE

• Crime Scene
• Investigation

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INVESTIGATORS

• 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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First Officer at the Scene

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

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Primary and Secondary Crime Scenes

• Primary where the crime actually takes place,
  for example, in a bank robbery the bank is the
  primary scene.
• The secondary scene is somehow related to the
  crime but is not where the actual crime took
  place, for example with the bank robbery, the
  get-away car and the thiefs hideout.

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Once the Scene has Been Secured

• a lead investigator will start the process of
  evaluating the area.
• First the boundaries of the scene must be
  determined, then establish the perps path of
  entry and exit.

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Types of Evidence

• Testimonial evidence includes oral or written
  statements given to police as well as court
  testimony by people who witnessed an event.
• Physical evidence refers to any material items
  that would be present at the crime scene, on the
  victims, or found in a suspects possession.
• Trace evidence refers to physical evidence that
  is found in small but measurable amounts, such as
  strands of hair, fibers, or skin cells.

What will evidence collected at a scene do for
the investigation?

• May prove that a crime has been committed
• Establish key elements of a crime
• Link a suspect with a crime scene or a victim
• Establish the identity of a victim or suspect
• Corroborate verbal witness testimony
• Exonerate the innocent.
• Give detectives leads to work with in the case

Source http//www3.sc.maricopa.edu/ajs/crime_scen
e_technician.htm
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Crime Scene Protocol

• Step 1 Interview
• The first step in investigating a crime scene is
  to interview the first officer at the scene or
  the victim to determine what allegedly happened,
  what crime took place, and how was the crime
  committed. This information may not be factual
  information but it will give the investigators a
  place to start.
• Step 2 Examine
• The second step in the investigation of a crime
  scene, which will help identify possible
  evidence, identify the point of entry and point
  of exit, and outline the general layout of the
  crime scene.
• Step 3 Document
• The third step in the protocol involves creating
  a pictorial record of the scene as well as a
  rough sketch to demonstrate the layout of the
  crime scene and to identify the exact position of
  the deceased victim or other evidence within the
  crime scene.
• Step 4 Process
• This is the last step in the protocol. The crime
  scene technician will process the crime scene for
  evidence, both physical and testimonial evidence.
  It is the crime scene technicians responsibility
  to identify, evaluate and collect physical
  evidence from the crime scene for further
  analysis by a crime laboratory.

Adapted from http//www.feinc.net/cs-proc.htm
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Take photographs

• As soon as possible of the unaltered scene
• Prior to moving or removing any evidence
• Close-ups of each item of evidence (use a scale)

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Sketches

• are important because they relationships of items
  to other things
• They must be clear and show the coordinate
  position of each item of evidence

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A rough sketch A finished sketch
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Crime Scene Search Patterns

• Spiral Search Grid Method
• Method
• Search pattern often extends out from
• key evidence or victim. Depends on area,
• Actions of suspects and victim.

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More search Methods

• Strip, or line search, often used underwater or
  for very large areas.

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1 more search method

• Quadrant, or zone search

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Processing Physical Evidence

• In order for evidence
• to be admissible, it
• must be
• Legally obtained
• Probativeactually prove something (relevant)
• Identify the item
• Maintain the chain of possession

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Physical Evidence

• Transient Evidence--temporary easily changed or
  lost usually observed by the first officer at
  the scene
• Odor--putrefaction, perfume, gasoline, urine,
  burning, explosives, cigarette or cigar smoke
• Temperature--of room, car hood, coffee, water in
  a bathtub cadaver
• Imprints and indentations--footprints teeth
  marks in perishable foods tire marks on certain
  surfaces
• Markings

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Physical Evidence (cont)

• Pattern or Transfer Evidence--produced by direct
  contact between a person and an object or between
  two objects. There are several ways (at least 7)
  of classifying evidence. In this class, we will
  use
• Biological
• Chemical
• Physical
• Miscellaneous

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Biological Evidence

• Blood
• Semen
• Saliva
• Sweat/Tears
• Hair
• Bone

• Tissues
• Urine
• Feces
• Animal Material
• Insects
• Bacterial/Fungal

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Chemical Evidence

• Fibers
• Glass
• Soil
• Gunpowder
• Metal
• Mineral
• Narcotics
• Drugs

• Paper
• Ink
• Cosmetics
• Paint
• Plastic
• Lubricants
• Fertilizer

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Physical (impression)

• Fingerprints
• Footprints
• Shoe prints
• Handwriting
• Firearms

• Printing
• Number restoration
• Tire marks
• Tool marks
• Typewriting

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Miscellaneous

• Laundry marks
• Voice analysis
• Polygraph

• Photography
• Stress evaluation
• Pyscholinguistic analysis
• Vehicle identification

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Physical Evidence (cont)

• Conditional Evidence--produced by a specific
  event or action important in crime scene
  reconstruction and in determining the set of
  circumstances within a particular event.
• Light--headlight lighting conditions
• Smoke--color, direction of travel, density, odor
• Fire--color and direction of the flames, speed of
  spread, temperature and condition of fire

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Conditional Evidence (cont.)

• Location--of injuries or wounds of bloodstains
  of the victims vehicleof weapons or cartridge
  cases of broken glass, etc.
• Vehicles--doors locked or unlocked, windows
  opened or closed radio off or on (station)
  odometer mileage
• Body--position types of wounds rigor, livor and
  algor mortis
• Scene--condition of furniture, doors and windows
  any disturbance or signs of a struggle.

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THE BODYRigor Mortis
Temperature Stiffness
Time Since of body of body
Death

• Warm
• Warm
• Cold
• Cold

• Not stiff
• Stiff
• Stiff
• Not stiff

• Not dead more than 3 hrs
• Dead between 3 and 8 hrs
• Dead 8 to 36 hours
• Dead more than 36 hours

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THE BODYLivor Mortis

• Livor mortis is the settling of the blood,
  causing the skin to change colors.
• Lividity indicates the position of the body after
  death. When lividity becomes fixed, then the
  distribution of the lividity pattern will not
  change even if the bodys position is altered.
• Lividity usually becomes fixed between 10 and 15
  hours after death.

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THE BODYAlgor Mortis

• Algor mortis is body temperature. At a crime
  scene, it can be obtained in two different ways.
• Rectal temperature
• Liver temperature

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Time Frame of Death

• Condition Appearance
• Periphery blood drying 30 min to 2 hrs
• Blue-green discoloration of skin
• Right and left area of abdomen 24 hours
• Entire abdomen 36 hours
• Bloating 36 to 48 hours
• Skin slippage 4 to7 days
• Absence of smell from bones more than 1 year

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Time Frame of DeathEyeball Changes

• Condition Appearance
• Cornea drying (eyes open) minutes
• Cornea drying (eyes closed) 2 hours
• Corneal cloudiness (eyes open) less than 2 hours
• Corneal cloudiness (eyes closed) 12 to 24 hours
• Eyeball collapse more than 24 hrs

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THEREFORE,
One can die of a massive hemorrhage (the
mechanism of death) due to a gun shot wound
through the head (cause of death) as a result of
being shot (homicide), shooting yourself
(suicide), dropping a gun and it discharging
(accident), or not being able to tell which
(undetermined). All of which are manners of
death.
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Crime Scene Challenge

• Now that your eyes and brain are warmed up, lets
  test your observation skills a bit more.
• You will have 2 minutes to study the photograph
  of a crime scene on the next slide.
• Try to pay attention to details as you will be
  asked 10 questions about the crime scene!
• You are not allowed to write anything down until
  after the time is up.
• Ready?

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Do you remember?

• What color coffee mug was in the picture? Blue
  Red Yellow
• 2. When was the deadline? Yesterday
  Today Tomorrow
• 3. What time was on the clock on the wall?
  1040 1105 155
• 4. How many sticky notes were on the whiteboard?
  Four Six Eight
• 5. Which of the following was NOT in the picture?
  Stapler Trash Can Printer
•  6. What was the name on the plaque on the desk?
  Bill Brian Carl
•  7. What color was the victim's shirt? Black
  Blue Red
•  8. How many plants were in the picture?
  None One Two
• 9. What was the color of the marker in the desk
  drawer? Red Blue Green
• 10. Where was the book in the picture? On a
  box In the trash can Under the body