Forensic Science

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Forensic Science

• Mr. Snyder
• Room S206
• Kickapoo High School

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M E E T M R S N Y D E R
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Class Website
http//rsnyder20.tripod.com
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What is Forensic Science?

• Forensic science is the application of natural
  sciences to matters of the law. In practice,
  forensic science draws upon physics, chemistry,
  biology, and other scientific principles and
  methods. Forensic science is concerned with the
  recognition, identification, individualization,
  and evaluation of physical evidence. Forensic
  scientists present their findings as expert
  witnesses in the court of law.
• The word forensic means pertaining to the
  law forensic science resolves legal issues by
  applying scientific principles to them.

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A Career in Forensic Science

• Must have a bachelor's degree, best if in
  chemistry, biology, or forensic science.
• Columbia College, Missouri, Southeast Missouri
  State University, Saint Louis University School
  of Medicine, Saint Louis University, Oklahoma
  State University, Arkansas State University,
  University of Arkansas, Little Rock
• Starting Salaries range from 30,000- 35,000 a
  year to 80,000-120,000 a year with 20 years
  experience.

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Units of a Forensics Team

• Biological Unit

• Physical Science Unit

• Bloodstains
• Body fluids
• Hair and fiber
• Botanical materials (wood and plants).

• Chemistry (drugs, explosives)
• Physics (glass, scratches)
• Geology (soil, rocks)

Photography Unit
Firearms Unit

• Records the crime scene
• Photographs
• Sketches
• Notes

• Firearms
• Bullets
• Cartridge Shells
• Ammunition
• Garments

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Part 1 Crime Scene Basics
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Approaching a Crime Scene Protocol

• Personal Safety and the well being of victims
• Preserve and Isolate the crime scene
• Record the crime scene

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Crime Scene Vocabulary

• CRIME SCENE Any physical location in which a
  crime has occurred or is suspected of having
  occurred.

PRIMARY CRIME SCENE The original location of a
crime or accident.
SECONDARY CRIME SCENE An alternate location
where additional evidence may be found.
SUSPECT Person thought to be capable of
committing a crime.
ACCOMPLICE Person associated with someone
suspected of committing a crime.
ALIBI Statement of where a suspect was at the
time of a crime.
Source http//www3.sc.maricopa.edu/ajs/crime_scen
e_technician.htm
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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 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 is often present to help
determine if any search warrants are required to
proceed and obtains those warrants from a judge.
The MEDICAL EXAMINER (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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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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Forensic Investigators must learn to be excellent
observers

• They must be able to find, document, and
  interpret evidence
• Observation - recognizing and noting some FACT to
  gather information about the world
• You make observations using your five senses
• Observations must be specific and accurate, not
  relative, so that it means the same to everyone.
• Example
• Incorrect - the burning bag smelled nasty
• Correct - the burning bag smelled similar to
  rotten eggs
• Observations can be qualitative or quantitative
• Qualitative observations - factual descriptions
  that do not use numbers
• Example Mr. Snyder has brown eyes
• Quantitative observations - factual descriptions
  that do use numbers
• Example Mr. Snyder has two eyes

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The Power of Observation

• You have thirty (30) seconds to observe the
  following image and remember everything that you
  can about this image. YOU MAY NOT WRITE ANYTHING
  DOWN AND YOU MAY NOT DISCUSS WHAT YOU OBSERVE
  WITH ANY MEMBER OF YOUR FORENSIC TEAM
• ARE YOU READY?

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The Power of Observation Activity

• 1. What color is the truck?
• 2. What is the speed limit?
• 3. Is there a van present? What color?
• 4. Other than a speed limit sign, what other
  sign(s) are present? What do they say?
• 5. Is there a sidewalk?
• 6. What is found alongside the nearest driveway?
• 7. Where is there a stop sign?
• 8. Are vehicles parked along the road? If so, how
  many?
• 9. How many telephone poles are there?
• 10. What color is the nearest sign to you?

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Observation Activity 2

• Choose two members of your forensic team to be
  observers and choose two people to be
  investigators.
• Allow the observers to look at the picture for 30
  seconds. The investigators should not look at the
  picture.
• After 30 seconds, the investigators should begin
  questioning the observers. Each Investigator
  should question each observer. Then, the
  Investigators should attempt to reconstruct the
  scene based on the "eyewitness testimony".

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What is testimonial evidence?
Testimonial evidence includes oral or written
statements given to police as well as testimony
in court by people who witnessed an event.
Eyewitness accounts can be a useful tool in
helping investigators with analyzing a crime
scene, but are not viewed to be highly reliable.
In addition, eyewitness identifications (right or
wrong) can have a big influence on the outcome of
an investigation or trial. People are likely to
view the same scene in different ways depending
on their positions, line of sight, familiarity
with the area, and other factors that can
interfere with a persons ability to remember
details.
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The Power of Perception

• Not always reliable
• Does not always reflect reality

How many legs do you see?
Which way is the girl facing?
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Who is in this picture?
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What do you see?
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What do you see?
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Why is perception faulty?

• Our brains can filter out or change information
• And

The Bunny Effect video
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Can you read this?
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Does this image appear to be moving?

• Its NOT!
• Just kidding, this one is actually moving

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Did you know?
According to The Innocence Project (2008)
"Eyewitness misidentification is the single
greatest cause of wrongful convictions
nationwide, playing a role in more than 75 of
convictions overturned through DNA testing."
Still, the criminal justice system profoundly
relies on eyewitness identification and testimony
for investigating and prosecuting crimes (Wells
Olson, 2003).
What factors affect a persons memory and their
ability to identify a suspect?
Source http//www.helium.com/items/1276135-accura
te-eyewitness-accounts
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Witness Factors

• Age may play a role in the accuracy of an
  eyewitness statement or identification of a
  suspect. Studies have shown that when a lineup
  contains the actual culprit, both young children
  and elderly perform well, but when the lineup
  does not contain the culprit there is a higher
  rate of mistaken identifications.
• The race of the witness may also play a role. The
  Cross Race Effect (CRE) is a phenomenon in which
  people are better at recognizing faces of their
  own race rather than those of other races.
• The use of drugs can alter a persons ability to
  recall the events of a crime even after they are
  no longer under the influence.
• A persons memory of an event can be influenced
  by other witnesses, investigators, and/or the
  media. Investigators use open-ended questioning
  and follow procedures for conducting line-ups to
  limit their influence on a witness memory of an
  event or identification of a suspect.

Source http//www.helium.com/items/1276135-accura
te-eyewitness-accounts
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Crime Scene Suspect Factors

• A crime that is extremely traumatic for an
  eyewitness may affect his/her recall of the
  event. For example, a witness confronted with a
  weapon tends to focus on the weapon rather than
  the perpetrators face.
• Someone who is able to focus on a perpetrator's
  face for a minute or longer will tend to have a
  more accurate memory than someone who saw the
  person for only a few seconds.
• Studies have shown that faces that are either
  highly attractive, highly unattractive, or
  distinctive are more likely to be accurately
  recognized. Simple disguises, such as hats or
  sunglasses, can interfere with accurate
  eyewitness identification. However, body
  piercings and tattoos increases the likelihood of
  an accurate identification.
• The time of day in which the crime occurred as
  well as a persons view of the scene may affect
  what a he/she is able to see. In addition, a
  person who is familiar with the area in which the
  crime took place, may have a better recall of the
  positions of the victims or suspects.

Source http//www.helium.com/items/1276135-accura
te-eyewitness-accounts
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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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Answer each question below.
1. 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
Source http//forensics.rice.edu/html/picture_beg
in.html
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Facial Composites
Investigators work with sketch artists and
eyewitnesses to create facial composites, or
sketches of a persons face. Today many police
departments are using facial reconstruction
software to help them with this task.
The composite may be used internally to assist
officers in identifying the suspect or used
externally through local media (radio, TV, and
newspaper) to solicit leads from citizens.
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You will have a chance to try to create a facial
composite later in the course. You will need to
pay close attention to the following features
The shape of the face The shape of the jaw The
shape of the eyes The shape of the nose The width
of the neck The shape protrusion of the
ears The presence of facial piercing The presence
of facial hair, its color, location The
presence of facial markings, such as scars or
tattoos Forehead or other facial lines The
presence of eyeglasses or sunglasses The length,
color, texture of the persons hair
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Forensic Science

• This concludes an
• Introduction to forensic science