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Forensic Science

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  1. Forensic Science Mr. Snyder Room S206 Kickapoo High School

  2. M E E T M R S N Y D E R

  3. Class Website

  4. 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.

  5. 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.

  6. Units of a Forensics Team Physical Science Unit Biological 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

  7. Part 1: Crime Scene Basics

  8. Approaching a Crime Scene Protocol • Personal Safety and the well being of victims • Preserve and Isolate the crime scene • Record the crime scene

  9. 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:

  10. 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 suspect’s 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:

  11. 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:

  12. 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

  13. Forensic Investigators must learn to be excellent observers • They must be able to find, document, and interpretevidence • 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 • Qualitativeobservations - factual descriptions that do not use numbers • Example: Mr. Snyder has brown eyes • Quantitativeobservations - factual descriptions that do use numbers • Example: Mr. Snyder has two eyes

  14. The Power of Observation You have thirty (30) seconds to observe the following image and remembereverythingthatyoucan 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?

  15. 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?

  16. 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".

  17. 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 person’s ability to remember details.

  18. The Power of Perception • Not alwaysreliable • Does not alwaysreflect reality Whichwayis the girl facing? How many legs do yousee?

  19. Whois in thispicture?

  20. What do yousee?

  21. What do yousee?

  22. Whyis perception faulty? • Our brainscanfilter out or change information • And…… The BunnyEffectvideo

  23. Can youreadthis?

  24. Does this image appear to be moving? • It’s NOT! • Just kidding, this one is actually moving

  25. 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 person’s memory and their ability to identify a suspect? Source:

  26. 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 person’s ability to recall the events of a crime even after they are no longer under the influence. A person’s 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. Witness Factors Source:

  27. 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 perpetrator’s 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 person’s 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. Crime Scene & Suspect Factors Source:

  28. Crime Scene Challenge • Now that your eyes and brain are warmed up, let’s 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?

  29. 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? 10:40 11:05 1:55 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:

  30. FACES – A software program that offers many options to help you recreate a person’s facial features. Facial Composites Investigators work with sketch artists and eyewitnesses to create facial composites, or sketches of a person’s 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.

  31. 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 person’s hair

  32. Forensic Science This concludes an Introduction to forensic science