INTRODUCTION to Crime Scene Investigation FORENSIC SCIENCE INTRODUCTION to Crime Scene Investigation

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?

Answers to Critical Thinking 336-8478 dentist (222)686-8268 accountant 774-6837 printer 487-2263 husband 247-5463 airline 832-2437 teacher

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

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

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

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

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

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

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

Crime Scene Search Patterns TWO of FOUR PATTERNS Spiral Grid

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

Crime Scene Sketch c A. Couch/sofa B. Female body C. Knife Date: August 14, 2001 Criminalist: Ann Wilson Time: 11:35 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 D G A E E E F E

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

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

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

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.

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

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.

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

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

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.

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

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

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

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.

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.

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?