Unit 1: Introduction to Forensic Science and Evidence

What is forensic science?

Forensic Science Definition: The study and application of science to matters of law.

Jobs of Forensic Scientists: Analyze & examine Evidence Follow scientific protocols Provide timely, accurate, and thorough information Testify in court regarding results of analysis

Types of Forensic Scientists: Anthropologist Odontologist Entomologist Pathologist Toxicologist Serologist Crime Scene Technician

Crime Lab Units Physical Science Unit Glass/Fibers/Soil/Impressions/ Markings Biology Unit Serology (blood) DNA Analysis & Blood Splatter Anthropology (Human Remains) Pathology (disease) Odontology (teeth) Firearms Unit Ballistics Document Examination Unit Forgery Toxicology Drugs Latent Fingerprint Polygraph Voiceprint Analysis Cybertechnology Psychiatry Accounting Arson Evidence Collection Crime Scene Investigators

Major Crime Laboratories FBI-Federal Bureau of Investigation Full Service DEA-Drug Enforcement Administration Drug Investigations ATF-Alcohol Tobacco and Firearms Firearms/Bombs U.S. Postal Service Crimes involving mail U.S. Fish and Wildlife Service Environmental Services

What is evidence? What do you think the definition of evidence is? What types of evidence can you think of?

What is evidence? Definition: anything that tends to establish or disprove a fact

Federal Rules of Evidence In order for evidence to be admissible, it must be: Probative—actually prove something The more directly linked to a suspect the more probative it is Example: Fingerprints are more probative than fibers or glass found at the scene Material—address an issue that is relevant to the particular crime

Admissibility of Evidence 1923 Frye v. United States Scientific evidence is allowed into the courtroom if it is generally accepted by the relevant scientific community. The Frye standard does not offer any guidance on reliability. The evidence is presented in the trial and the jury decides if it can be used.

Categories of Evidence Direct Evidence Proves a direct fact Examples: Eyewitness Testimony Surveillance Video Circumstantial Evidence (aka Indirect Evidence) Implies a fact (but does not prove it directly) Most types of evidence fall under this category Physical and Biological Evidence Hair/Blood/Fingerprints/Documents/Glass/Impressions etc.

Classification of Evidence by Nature Biological—blood, semen, saliva, sweat, tears, hair, bone, tissues, urine, feces, animal material, insects, bacterial, fungal, botanical Chemical—fibers, glass, soil, gunpowder, metal, mineral, narcotics, drugs, paper, ink, cosmetics, paint, plastic, lubricants, fertilizer Physical—fingerprints, footprints, shoe prints, handwriting, firearms, tire marks, tool marks, typewriting Miscellaneous—laundry marks, voice analysis, polygraph, photography, stress evaluation, psycholinguistic analysis, vehicle identification

Evidence Characteristics Class—common to a group of objects or persons Individual—can be identified with a particular person or a single source Fibers Shoe Prints Fingerprints Shoe Prints Blood DNA Typing

Class or Individual? These fibers are class evidence; there is no way to determine if they came from this garment. The large piece of glass fits exactly to the bottle; it is individual evidence.

Eyewitness Testimony (Testimonial Evidence) Statement under oath by a competent witness

Expert Testimony Testimony made by a qualified person about a scientific, technical, or professional issue. Effectiveness Depends On: Their experience level Their education How well they communicate Cannot be hearsay Secondhand information I heard that he…

How to be a Good Observer Observe systematically— Start at one part of a crime scene and run your eyes slowly over every space. Slowly look at every part of a piece of evidence. Do not assume that later on you will be able to remember everything.

How to be a Good Observer Turn off filters— Do not pay attention to only what you think is important. On a crime scene you will not know what will turn out to be important. Make a conscious effort to pay attention to all the details in your surroundings.

How to be a Good Observer Interpret Data Later— Do look for patterns and make connections. But the more information obtained, the better will be the interpretations. Remember that eyewitness accounts and your own thinking can include prejudices.

How to be a Good Observer Documentation— It is important to write down and photograph as much information as possible. Keep in mind that memory is faulty. Remember that our brains tend to automatically fill in gaps in our perceptions.

Are You a Good Eyewitness?? You will have 30 seconds to look at a picture and study it. When time up, I will ask you several questions about the picture. Answer the questions on the handout When we are done we will find out who would make a good eyewitness!!!

READY?

PICTURE 1

Questions At what location was the photograph taken? How many cars are pictured? What color are the cars?  What types of offices are located in the building?  How many small trees are in the picture? The photograph was taken in New York State during which season? How many people are in the photograph?

READY?

PICTURE 2

Questions What is pictured in Photograph 2? Describe the shape of the object pictured. What are the colors of the object? What color edged the top of the object? Upon what is the object displayed? Describe or sketch the design on the object. What is the approximate size of the object?

READY?

PICTURE 3

Questions How many people are in Photograph 3? What is the sex of the person in the picture? What is the approximate age of the person in the photograph? What color is the person’s hair? Does the person have long hair or short hair? Does the person have any distinguishing features? Glasses? Can you describe the person’s clothing? Can you describe where the picture was taken? Based on evidence in the photograph, can you form a hypothesis about the person’s occupation? Is it possible to identify the interests of the person based on evidence in the room?

Discussion Questions 1. Did everyone answer all of the questions correctly? 2. Did everyone have the same answers? If not, why? 3. Did you do better with practice? 4. Do you think your observations changed when you were distracted? 5. Would your answers have been good enough to testify in court?

Problems with Testimonial Evidence

Observations by Witnesses Affected By: Emotional states (stress level) More stress = Less detail Prejudice Ulterior Motives Interrogation/Questioning Tactics Used Time

The Innocence Project Barry C. Scheck and Peter J. Neufeld at the Benjamin N. Cardozo School of Law, starting in 1992, use DNA to examine post-conviction cases. The project has found that up to 87% of the wrongful convictions they discovered were due to faulty eyewitness identifications.

Original Composite Sketch of Cotton

The Case of Ronald Cotton Part 1

The Case of Ronald Cotton Part 2

Value of Physical Evidence Generally more reliable than testimonial Can prove that a crime has been committed Can corroborate or refute testimony Can link a suspect with a victim or with a crime scene Can establish the identity of persons associated with a crime Can allow reconstruction of events of a crime

Reconstruction Physical Evidence is used to answer questions about: what took place how the victim was killed number of people involved sequence of events A forensic scientist will compare the questioned or unknown sample with a sample of known origin (control sample).

Types of Physical Evidence Transient Evidence—temporary; easily changed or lost; usually observed by the first officer at the scene Pattern Evidence—produced by direct contact between a person and an object or between two objects Conditional Evidence—produced by a specific event or action; important in crime scene reconstruction and in determining the set of circumstances or sequence within a particular event Transfer Evidence—produced by contact between person(s) or object(s), or between person(s) and person(s) Associative Evidence—items that may associate a victim or suspect with a scene or each other; ie, personal belongings

Examples of Transient 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—surroundings, car hood, coffee, water in a bathtub, cadaver Imprints and indentations—footprints, teeth marks in perishable foods, tire marks on certain surfaces Markings

Examples of Pattern Evidence Pattern Evidence—most are in the form of imprints, indentations, striations, markings, fractures or deposits. Clothing or article distribution Gun powder residue Material damage Body position Tool marks Modus operandi (how they did it) Blood spatter Glass fracture Fire burn pattern Furniture position Projectile trajectory Tire marks or skid marks

Examples of Conditional Evidence Conditional Evidence—produced by a specific event or action; important in crime scene reconstruction and in determining the set of circumstances or sequence 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 Location—of injuries or wounds, of bloodstains, of the victim’s vehicle, of weapons or cartridge cases, of broken glass Vehicles—doors locked or unlocked, windows opened or closed, radio off or on (station), odometer mileage Body—position, types of wounds; rigor mortis Scene—condition of furniture, doors and windows, any disturbance or signs of a struggle

Examples of Transfer Evidence Locard’s Principle: the perpetrator of a crime will bring something into the crime scene and leave with something from it, and that both can be used as forensic evidence Hair/Fibers Fingerprints Blood (due to contact---not from wounds) Footprints/Impressions Paint/Chemicals Body Fluids

Examples of Associative Evidence Associative Evidence—items that may associate a victim or suspect with a scene or each other; ie, personal belongings Identification Cards Security Camera Footage Receipts Personal Belongings Jewelry etc…

COLLECTING AND PACKAGING EVIDENCE Why do you think it is important to collect and package evidence correctly? What could happen to evidence if it isn’t handled correctly? What type of errors do you think investigators typically make?

COLLECTING AND PACKAGING EVIDENCE One individual should be designated as the evidence collector to ensure that the evidence is collected consistently Each item must be placed in a separate container, sealed, and labeled Most fragile is collected and packaged first Different types of evidence require specific or special collection and packaging techniques The body is the property of the coroner or medical examiner. The collection of evidence on the body is done by that department Should also collect controls from a known suspect or victim (this is a control) to compare to unknown evidence from the crime scene.

PACKAGING Blood evidence should be packaged to avoid mold/mildew Most items should be packaged in a primary container and then placed inside a secondary one. These are then placed inside other containers such as paper bags, plastic bags, canisters, packets and envelopes depending on the type and size of the evidence. Blood evidence should be packaged to avoid mold/mildew Never in plastic-always in paper or sealed test tube Arson evidence should be in an airtight container Prevents evaporation of possible fume evidence Glass evidence should be packaged in a rigid container to avoid cuts

CHAIN OF CUSTODY There must be a written record of all people who have had possession of an item of evidence. The evidence container must be marked for identification The collector’s initials should be placed on the seal If evidence is turned over to another person, the transfer must be recorded.

Chapter 3 THE CRIME SCENE A crime scene is anywhere evidence can be found that is associated with a case Primary Crime Scene- where crime was committed Secondary Crime Scene- evidence found in a place where crime was not committed Example: Where the victim was murdered is the primary crime scene, where the perpetrator moved the body after is the secondary crime scene Kendall/Hunt

CRIME SCENE TEAM A group of professional 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

FIRST OFFICER ON THE SCENE A Assess the crime scene and assist those hurt D Detain the witness A Arrest the perpetrator P Protect the crime scene T Take notes

PROCESSING A CRIME SCENE Isolate and secure the scene Document the scene Search for evidence Collect and package evidence, maintaining the chain of custody Submit evidence to the crime lab

CRIME SCENE SURVEY Walk-through—performed by the crime scene investigator, the first officer and sometimes the lead detective Purpose: Mentally prepare a reconstruction theory Note any transient or conditional evidence that could change over time. Note weather conditions Note points of entry or exit, as well as paths of travel within the crime scene Record initial observations of who, what, where, when, and how Identify special needs within the crime scene for personnel, precautions or equipment and notify superior officers or other agencies

DOCUMENTATION Notes—date and time, description of the location, weather and environmental conditions, description of the crime, location of the evidence relative to other key points, the names of all people involved, modifications that have occurred and other relevant information Photography—photos of scene and surroundings, mid-range to close-up photos with various angles of each piece of evidence, photos as viewed by any witnesses. Sketches—inclusion of date, time, scale, reference points, distance measurements, names of investigators, victims, suspects, and a legend (key) Videography—allows narration (non-subjective) to be included

SEARCH METHODS Line or strip method—best in large, outdoor scenes Grid method—basically a double-line search; effective, but time-consuming Zone method—most effective in houses or buildings; teams are assigned small zones for searching Wheel or ray method—best on small, circular crime scenes Spiral method—may move inward or outward; best used where there are no physical barriers

CRIME SCENE RECONSTRUCTION Stages Data collection Hypothesis formation Examination, testing and analysis Determination of the significance of the evidence Theory formulation

CRIME SCENE SKETCHES -Drawn to Scale -All evidence is labeled 4358 Rockledge Dr, St. Louis, Mo. Date: August 14, 2005 Time: 11:35 am Homicide Ann Wilson -Drawn to Scale -All evidence is labeled -Measurements are given -Sketch Information Recorded

Step 1: Draw a rough outline of the area- include windows (represented by the rectangles) and doors (represented by openings in the outline) Step 2: Measure the room or space in which the crime occurred. Label the dimensions on the sketch

Step 3: Sketch in the furniture and location of evidence using basic shapes Step 4: Label each item in the diagram with a number or letter, then write the name in a key.

Step 6: MEASURING FROM FIXED POINTS Step 5: Label the diagram with the date, time, location, and victim’s name (if known) Note: An unknown victim is commonly given the name of John Doe or Jane Doe Step 6: MEASURING FROM FIXED POINTS Make two measurements from fixed (not moveable) points to each piece of evidence These measurements are noted on a separate document, and not on actual sketch Put on back of sketch See Board

Examples OF sketches