Have You Seen Any of These Television Shows? • CSI • Criminal Minds • NCIS • Law and Order • Bones
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Have you seen any of these television shows? • CSI • Criminal Minds • NCIS • Law and Order • Bones Forensic Science T. Trimpe 2006 http://sciencespot.net 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: http://www3.sc.maricopa.edu/ajs/crime_scene_technician.htm 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: http://www3.sc.maricopa.edu/ajs/crime_scene_technician.htm 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: http://science.howstuffworks.com/csi.htm 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 http://www.feinc.net/cs-proc.htm Forensic Science disciplines at the Investigating the Evidence Illinois State Police Crime Labs Drug Chemistry – Determines the presence of controlled substances and the identification of marijuana Trace Chemistry - Identification and comparison of materials from fires, explosions, paints, and glass. Microscopy – Microscopic identification and comparison of evidence, such as hairs, fibers, woods, soils, building materials, insulation and other materials. Biology/DNA – Analysis of body fluids and dried stains such as blood, semen, and saliva. Toxicology – Tests body fluids and tissues to determine the presence of drugs and poisons. Latent Prints - Identification and comparison of fingerprints or other hidden impressions from sources like feet, shoes, ears, lips or the tread on vehicle tires. Ballistics (Firearms) – Study of bullets and ammunition through the comparison of fired bullets, cartridges, guns, and gunpowder patterns on people and objects. Toolmarks – Examines marks left by tools on objects at a crime scene or on a victim, such as a hammer used to break a door or a screwdriver used to pick a lock. Questioned Documents - Examination of documents to compare handwriting, ink, paper, writing instruments, printers, and other characteristics that would help to identify its origin. Source: http://www.isp.state.il.us/forensics/ What evidence would you collect? Mock Crime Scene: http://www.masss.gov Forensic Science T. Trimpe 2006 http://sciencespot.net/ What makes up our blood? • RED BLOOD CELLS (Erythrocytes) – The most abundant cells in our blood; they are produced in the bone marrow and contain a protein called hemoglobin that carries oxygen to our cells. • WHITE BLOOD CELLS (Leukocytes) – They are part of the immune system and destroy infectious agents called pathogens. • PLASMA – This is the yellowish liquid portion of blood that contains electrolytes, nutrients and vitamins, hormones, clotting factors, and proteins such as antibodies to fight infection. • PLATELETS (Thrombocytes) – The clotting factors that are carried in the plasma; they clot together in a process called coagulation to seal a wound and prevent a loss of blood. Blood Facts The average adult has about FIVE liters of blood inside of their body, which makes up 7-8% of their body weight. Blood is living tissue that carries oxygen and nutrients to all parts of the body, and carries carbon dioxide and other waste products back to the lungs, kidneys and liver for disposal. It also fights against infection and helps heal wounds, so we can stay healthy. There are about one billion red blood cells in two to three drops of blood. For every 600 red blood cells, there are about 40 platelets and one white cell. http://www.bloodbankofalaska.org/about_blood/index.html Genetics of Blood Types • Your blood type is established before you are BORN, by specific GENES inherited from your parents. • You inherit one gene from your MOTHER and one from your FATHER. • These genes determine your blood type by causing proteins called AGGLUTINOGENS to exist on the surface of all of your red blood cells. What are blood types? Blood Types There are 3 alleles or genes for blood AA or AO = Type A type: A, B, & O. Since we have 2 genes, BB or BO = Type B there are 6 possible combinations. OO = Type O AB = Type AB http://learn.genetics.utah.edu/units/basics/blood/types.cfm How common is your blood type? 46.1% 38.8% 11.1% 3.9% Blood Transfusions A blood transfusion is a procedure in which blood is given to a patient through an intravenous (IV) line in one of the blood vessels. Blood transfusions are done to replace blood lost during surgery or a serious injury. A transfusion also may be done if a person’s body can't make blood properly because of an illness. Who can give you blood? Universal Donor People with TYPE O blood are called Universal Donors, because they can give blood to any blood type. People with TYPE AB blood are called Universal Recipients, because they can receive any blood type. Rh + Can receive + or - Rh - Can only receive - Universal Recipient Rh Factors • Scientists sometimes study Rhesus monkeys to learn more about the human anatomy because there are certain similarities between the two species. While studying Rhesus monkeys, a certain blood protein was discovered. This protein is also present in the blood of some people. Other people, however, do not have the protein. • The presence of the protein, or lack of it, is referred to as the Rh (for Rhesus) factor. A+ A- • If your blood does contain the protein, your B+ B- blood is said to be Rh positive (Rh+). If your blood does not contain the protein, your blood AB+ AB- is said to be Rh negative (Rh-). O+ O- http://www.fi.edu/biosci/blood/rh.html Blood Evidence • Blood samples – Can be analyzed to determine blood type and DNA, which can be matched to possible suspects. • Blood droplets – Can be analyzed to give clues to the location of a crime, movement of a victim, and type of weapon. • Blood spatter – Can be analyzed to determine patterns that give investigators clues to how a crime might have happened. Microscopic Views Bird Blood Fish Blood Horse Blood Cat Blood Frog Blood Human Blood Dog Blood Snake Blood Forensic Science Lab Activity Warning: Some material in this presentation and related videos may be too graphic for some people. T. Trimpe 2006 http://sciencespot.net/ What does the abbreviation BPA represent? Bloodstain Pattern Analysis What can an investigator learn from the analysis of a blood spatter? Type and velocity of weapon Number of blows Handedness of assailant (right or left-handed) Position and movements of the victim and assailant during and after the attack Which wounds were inflicted first Type of injuries How long ago the crime was committed Whether death was immediate or delayed Source: http://science.howstuffworks.com/bloodstain-pattern-analysis1.htm http://www.crimescenetwo.com/img/popup/book2p2.jpg How is blood evidence detected at a crime scene? Light Source Investigators will first examine the crime scene to look for areas that may contain blood. They may use a high-intensity light or UV lights to help them find traces of blood as well as other bodily fluids that are not visible under normal lighting conditions.