FORENSIC SCIENCE INTRODUCTION Crime Scene Investigation Forensic Science

FORENSIC SCIENCE INTRODUCTION Crime Scene Investigation

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? ? ? 1. Analyze physical evidence 2. Provide Expert Testimony 3. Provide training in the recognition, collection and preservation of physical evidence 2

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

The History of Forensic Science *Sherlock Holmes: a fictional character developed by Sir Arthur Conan Doyle; used a great deal of forensic detection *Mathieu Orfila: toxicology (the detection of poisons) *Alphonse Bertillon: anthropometry (personal identification through body measurements) *Francis Galton: developed 1 st fingerprint identification system *Leone Lattes: determined methods of using blood type as a means of identification *Calvin Goddard: firearms examination *Albert Osborn: document examination *Edmund Locard: Developed the 1 st police lab *J. Edgar Hoover: director of the FBI: Organized the 1 st FBI Crime Lab in 1932 4

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 5

Branches of Forensic Science *Physical science: Using chemistry, physics, and geology to ID and compare crime scene evidence *Biology: blood, body fluids, hairs and fibers, entomology *Pathology, psychology, odontology, any more! 6

CORPUS DELICTI You must prove: “Body of the Crime” â that a crime occurred â that the person charged with the crime was responsible for the crime Top Reasons for Committing a Crime â Money â Revenge â Sex â Emotion--love, hate, anger Source of Evidence â Body â Primary and/or Secondary Crime Scene â Suspect(s) 7

4 Major FEDERAL Crime Labs: *FBI *Drug Enforcement Administration (DEA) *Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) *US Postal Inspection Service Most states also have their own, smaller crime labs 8

General Crime Lab Services and the materials each unit analyzes *Physical Science Unit: drugs, glass, paint, explosives, etc *Biology Unit: blood and other bodily fluids *Firearms Unit: ballistics, comparisons *Document Examination Unit: handwriting, typewriting, questioned documents (ransom notes, etc) *Photography Unit: record all phyhsical evidence. *Toxicology Unit: presence/absence of drugs *Latent Fingerprint Unit: fingerprints *Pathology Unit 9

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 * GO TO SLIDE 25…. . 10

Crime Scene Team A group of professionals investigators, each trained in a variety of special disciplines. Team Members ã ã ã First Police Officer on the scene Medics (if necessary) Investigator(s) Medical Examiner (if necessary) Photographer and/or Field Evidence Technician Lab Experts pathologist DNA expert forensic odontologist forensic psychologist firearm examiner document and handwriting experts serologist toxicologist forensic anthropologist forensic entomologist bomb and arson expert fingerprint expert 11

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 12

First Officer at the Scene ãA Assess the crime scene ãD Detain the witness ãA Arrest the perpetrator ãP Protect the crime scene ãT Take notes 13

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. Faces Composite Program by Inter. Quest 14

Crime Scene Search Patterns TWO of FOUR PATTERNS FSpiral FGrid 15

Crime Scene Search Patterns TWO of FOUR PATTERNS FStrip or Line FQuadrant or Zone 16

Crime Scene Sketch Date: August 14, 2001 Time: 11: 35 Criminalist: Ann Wilson Location: 4358 Rockledge Dr St. Louis, Mo. A. Couch/sofa E c B. Female body D C. Knife D. Over turned Lamp E. Chairs E F. Table G. Fireplace G A F E E E 17

Crime Scene Mapping (outdoors) âAzimuth--uses a compass beam to determine the location of each piece of evidence âTriangulation--uses two points at the crime scene to map each piece of evidence âCoordinate or grid--divides the crime scene into squares for mapping. âSuspended Polar Coordinate--for use in mapping evidence in a hole âBaseline--set a north/south line and measures 18 each piece of evidence from this line.

AZIMUTH Determines: • Direction • Distance • Elevation

TRIANGULATION Measure from A to B and then to the evidence in a triangular shape.

Coordinate or Grid Mapping Set a north/south line from a datum point established by a GPS. Make it a perfect square (4 x 4) by shooting the hypotenuse and setting in stakes every foot or meter. Measure and map the location of each piece of evidence. Then collect evidence and place in containers by grid.

Baseline Mapping Set a north/south line from the furthest most points of the crime scene. Then measure each piece of evidence from that baseline. Evidence will need a numerical measurement where the piece begins, ends and in the middle. Evidence Baseline

Suspended Polar Coordinate Measure and map each layer of evidence as you move down the hole. Use the compass readings from the top to measure degrees and a tank dipping line to measure depth.

MAPPING TECHNOLOGY The latest technology includes this Nikon Tsunami with computer. The exact location of all crime evidence can be determined and directly loaded into a computer to produce a crime scene map. Cost = $35, 000 for the set. 24

Physical Evidence Transient Evidence--temporary; ã ã 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 25

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: âBiological âChemical âPhysical âMiscellaneous 26

Biological Evidence â Blood â Semen â Saliva â Sweat/Tears â Hair â Bone â Tissues â Urine â Feces â Animal Material â Insects â Bacterial/Fungal 27

Chemical Evidence â Fibers â Glass â Soil â Gunpowder â Metal â Mineral â Narcotics â Drugs â Paper â Ink â Cosmetics â Paint â Plastic â Lubricants â Fertilizer 28

Physical (impression) â Fingerprints â Footprints â Shoe prints â Handwriting â Firearms â Printing â Number restoration â Tire marks â Tool marks â Typewriting 29

Miscellaneous â Laundry marks â Voice analysis â Polygraph â Photography â Stress evaluation â Pyscholinguistic analysis â Vehicle identification 30

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. âLight--headlight; lighting conditions âSmoke--color, direction of travel, density, odor âFire--color and direction of the flames, speed of spread, temperature and condition of fire 31

Conditional Evidence (cont. ) â Location--of injuries or wounds; of bloodstains; of the victims vehicle; of weapons or cartridge cases; of broken glass, etc. â Vehicles--doors locked or unlocked, windows opened or closed; radio off or on (station); odometer mileage â Body--position; types of wounds; rigor, livor and algor mortis â Scene--condition of furniture, doors and windows; any disturbance or signs of a struggle. 32

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 33

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. 34

Medical Examiner’s Responsibilities ã Identify the deceased ã Establish the time and date of death ã Determine a medical cause of death--the injury or disease that resulted in the person dying ã Determine the mechanism of death--the physiological reason that the person died ã Classify the manner of death ã ã ã Natural Accidental Suicide Homicide Undetermined ã Notify the next of kin 35

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

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. 37

THE BODY Algor Mortis Algor mortis is body temperature. Average human body temperature: 98. 6 F (37 C) 38

Time Frame of Death â Condition Appearance â Periphery blood drying 30 min to 2 hrs â Blue-green discoloration of skin â Right and left area of abdomen â Entire abdomen â Bloating â Skin slippage â Absence of smell from bones 24 hours 36 to 48 hours 4 to 7 days more than 1 year 39

Time Frame of Death Eyeball Changes â Condition Appearance â Cornea drying (eyes open) minutes â Cornea drying (eyes closed) 2 hours â Corneal cloudiness (eyes open) less than 2 hours â Corneal cloudiness (eyes closed) 12 to 24 hours â Eyeball collapse more than 24 hrs 40

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. 41

CRIME Why Did It Happened? What Happened? Crime Scene Evidence Collection Witness, Suspect and Motive Development Post Scene + Investigative Stage Profiling Means Motive Opportunity Who Did It? = Identification and Arrest of Suspect Evidence Processing Cause, manner, time of death 42

Forensic Investigations Include some or all of these seven major activities ãRecognition--ability to distinguish important evidence from unrelated material ãPattern recognition ãPhysical property observation ãInformation analysis ãField-testing ãPreservation--collection and proper preservation of evidence 43

Investigations (cont) â Identification--use of scientific testing âPhysical properties âChemical properties âMorphological (structural) properties âBiological properties âImmunological properties â Comparison--class characteristics are measured against those of know standards or controls; If all measurements are equal, then the two samples are considered to have come from the same source or origin. 44

Investigations (cont. ) â Individualization--demonstrating that the sample is unique, even among members of the same class. â Interpretation--gives meaning to all the information â Reconstruction--reconstructs the case events âInductive and deductive logic âStatistical data âPattern analysis âResults of laboratory analysis Lee, Dr. Henry. Famous Crimes. Southington: Strong Books, 2001 45

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 46 investigations?