1. INTRODUCTION to Crime Scene Investigation
FORENSIC SCIENCE
INTRODUCTION to
Crime Scene
Investigation

2. CRITICAL THINKING
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 from whom each message came?

3. Answers to Critical Thinking
dentist
(222) accountant
printer
husband
airline
teacher

4. What does a Forensic Scientist DO???
Forensic Science
Definition: The application of scientific technology to supply accurate and objective information reflecting the events that occurred at a crime.
What does a Forensic Scientist DO???
Analyze physical evidence
Provide Expert Testimony
Provide training in the recognition, collection and preservation of physical evidence

5. Complex Reasoning In Forensic Science
Deductive (reasoning from the general to the particular) and
Inductive Reasoning (reasoning from detailed facts to general principles)
Classifying
Comparing and Contrasting
Problem Solving
Analyzing Perspectives
Constructing Support
Error Analysis
Deduction--providing the proof that the situation is true.
Induction-drawing conclusions/generalization from information; listing support for the conclusions
Classifying--putting things into groups and determining the rules for the groups
Comparing--how are things alike and how are they different
Analyzing Perspectives--opinions about an issue and different ways to look at it
Constructing support--support and limitations for a particular argument
Error Analysis--determining what’s wrong and how it can be fixed

6. Locard’s Exchange Principle
Whenever 2 objects come in contact with one another, they exchange some material (dust particles, hair, dead skin cells…)
Locard strongly believed that every criminal can be connected to a crime by dust particles carried from the scene

7. Forensic Pathology
Investigation of sudden unnatural, unexplained or violent deaths
Answer the questions:
Who is the victim?
What are the injuries, when did they occur, and how were they produced?
5 manners of death: natural, homicide, suicide, accident, undetermined

8. Crime Scene Team
A group of professionals investigators, each trained in a variety of special disciplines.
Team Members
First Police Officer on the scene
Medics (if necessary)
Investigator(s)
Medical Examiner (if necessary)
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

9. 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

10. Eye Witness “Perception is reality.”
As a result an eye witness may not be the best source of crime scene information.
A police composite may be developed from the witness testimony by a computer program or forensic artist.
(Eye Witness Activity)
Faces Composite Program
by InterQuest

11. Crime Scene Search Patterns
TWO of FOUR PATTERNS
Spiral
Grid

12. Crime Scene Search Patterns
TWO of FOUR PATTERNS
Strip or Line
Quadrant or Zone

13. Crime Scene Sketch c A. Couch/sofa B. Female body C. Knife
Date: August 14, Criminalist: Ann Wilson
Time: 11: Location: 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 D G A E E E F E

14. 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

15. Physical Evidence (cont)
Pattern or Transfer Evidence--produced by direct contact between a person and an object or between two objects.

16. 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

17. Conditional Evidence (cont.)
Location--of injuries or wounds; of bloodstains; of the victims vehicle;of 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.

18. Evidence Characteristics
Class--common to a group of objects or persons
Individual--can be identified with a particular person or source.
ABO Blood Typing
Blood DNA Typing

19. Medical Examiner vs the Coroner
A medical examiner is a medical doctor, usually a pathologist and is appointed by the governing body of the area. There are 7 medical examiners in the state of Missouri and 400 forensic pathologists throughout the U.S.
A coroner is an elected official who usually has no special medical training. In four states the coroner is a medical doctor.

20. Medical Examiner’s Responsibilities
Identify the deceased
Establish the time and date of death
Determine a medical cause of death--the injury or disease that resulted in the person dying
Determine the mechanism of death--the physiological reason that the person died
Classify the manner of death
Natural
Accidental
Suicide
Homicide
Undetermined
Notify the next of kin

21. THE BODY Rigor Mortis Temperature Stiffness Time Since
of body of body Death
Warm
Cold
Not stiff
Stiff
Not dead more than 3 hrs
Dead between 3 and 8 hrs
Dead 8 to 36 hours
Dead more than 36 hours

22. THE BODY Livor 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 body’s position is altered.
Lividity usually becomes fixed between 10 and 15 hours after death.

23. THE BODY Algor Mortis Algor mortis is body temperature.
Average human body temperature: 98.6 F (37 C)

24. 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 to 48 hours
Skin slippage 4 to7 days
Absence of smell from bones more than 1 year

25. Time Frame of Death Eyeball 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

26. THEREFORE,
One can die of a massive hemorrhage (the mechanism of death) due to a fall (cause of death) as a result of being pushed (homicide), jumping (suicide), falling (accident), or not being able to tell which (undetermined). All of which are manners of death.

27. FACETS OF GUILT Means--the ability of have committed the crime
Motive--the reason for committing the crime. (This doesn’t have to be proven or presented in a court of law, but its what everyone wants to know.)
Opportunity--time or availability to have committed the crime.

28. Just A Thought
It’s not what you know that hurts you, its what you think you know and it’s not so Mark Twain
How does this apply to forensic science and crime investigations?