1 Have you seen any of these television shows? CSI Criminal Minds NCIS Law and Order Bones
3 T. Trimpe Forensic Science
4 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:
5 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:
6 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: Crime Scene Personnel
7 Step 1: Interview Crime Scene Protocol 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
8 Investigating the Evidence Forensic Science disciplines at the 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:
9 What evidence would you collect? Mock Crime Scene:
10 T. Trimpe Forensic Science
11 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.
12 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.
13 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.
14 What are blood types? There are 3 alleles or genes for blood type: A, B, & O. Since we have 2 genes, there are 6 possible combinations. Blood Types AA or AO = Type A BB or BO = Type B OO = Type O AB = Type AB
15 How common is your blood type? 46.1% 38.8% 11.1% 3.9%
16 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
17 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. If your blood does contain the protein, your blood is said to be Rh positive (Rh+). If your blood does not contain the protein, your blood is said to be Rh negative (Rh-). A+ A- B+ B- AB+ AB- O+ O-
18 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.
19 Microscopic Views Bird Blood Fish Blood Horse Blood Cat Blood Frog Blood Dog Blood Human Blood Snake Blood
20 Warning: Some material in this presentation and related videos may be too graphic for some people. Forensic Science Lab Activity T. Trimpe
21 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:
22 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. Blood Reagent Tests These tests, referred to as presumptive tests, are used to detect blood at crime scenes based upon the properties of hemoglobin in the blood. Further tests at the crime lab can determine if it is human blood or not. Examples: Phenolphthalein is a chemical that is still utilized today and is usually referred to as the Kastle-Meyer test and produces a pink color when it reacts with hemoglobin. HemaStix is a strip that has been coated with tetramethylbenzidine (TMB) and will produce a green or bluegreen color with the presence of hemoglobin. Kastle-Meyer Test Video HemaStix
23 Luminol This chemical is used by crime scene investigators to locate traces of blood, even if it has been cleaned or removed. Investigators spray a luminol solution is throughout the area under investigation and look for reactions with the iron present in blood, which causes a blue luminescence. One problem is that other substances also react, such as some metals, paints, cleaning products, and plant materials. Another problem is that the chemical reaction can destroy other evidence in the crime scene. Fluorescein This chemical is also capable of detecting latent or old blood, similar to luminol. It is ideal for fine stains or smears found throughout a crime scene. After the solution has been sprayed onto the substance or area suspected to contain blood, a UV light and goggles are used to detect any illuminated areas, which appear greenish-white if blood is present. It may also react to many of the same things as luminol (copper and bleach). Luminol Reaction Fluorescein Reaction in UV Light LCV or Leuco Crystal Violet, is one type of chemical process that is used for blood enhancement. Using this test helps to make the blood evidence more visible so it can be photographed and analyzed.
24 Bloodstain Pattern Analysis Terms Spatter Bloodstains created from the application of force to the area where the blood originated. Origin/Source The place from where the blood spatter came from or originated. Angle of Impact The angle at which a blood droplet strikes a surface. Parent Drop The droplet from which a satellite spatter originates. Satellite Spatters Small drops of blood that break of from the parent spatter when the blood droplet hits a surface. Spines The pointed edges of a stain that radiate out from the spatter; can help determine the direction from which the blood traveled. Satellite Spatters Parent Drop Spines
25 Types of Bloodstain Patterns Passive Bloodstains Patterns created from the force of gravity Drop, series of drops, flow patterns, blood pools, etc. Blood Spatter Movie Projected Bloodstains Patterns that occur when a force is applied to the source of the blood Includes low, medium, or high impact spatters, castoff, arterial spurting, expiratory blood blown out of the nose, mouth, or wound. Transfer or Contact Bloodstains These patterns are created when a wet, bloody object comes in contact with a target surface; may be used to identify an object or body part. A wipe pattern is created from an object moving through a bloodstain, while a swipe pattern is created from an object leaving a bloodstain. Images from
26 Blood Spatter Labs You will be creating sample drop patterns using single drops and multiple drops. We will also investigate the effect of motion and the angle of impact on blood spatter. This can be messy! Be very careful to keep the blood on the paper and not on yourself, the table, or floor. Hold you hand as steady as possible when making the drops. Brace your wrist against the meter stick to help you. Get your materials from your teacher paper, black marker, meter stick, goggles, and a bottle of blood. If you make a mess, clean it up immediately!
27 Lab 1: Single Droplets Label two large pieces of construction paper as shown below. Single Drops Group Members Single Drops Group Members Keep your drops in the correct area of the paper To do the lab, put on your goggles and hold the dropper bottle upside down so that the end of it is 25 cm from the paper. GENTLY squeeze the bottle so that ONE drop of blood is released and lands in the correct location on your paper. It should NOT hit the meterstick. Repeat TWO more times at this height for a total of three drops. Continue making drops of blood on your paper, but put the drop in a different area of the paper and change the height each time. When you are done, analyze your results and answer the questions on your worksheet. Make a mistake? Use a paper towel to wipe it off your paper!
28 Lab 1 Questions Use your results to answer these questions. What did you notice about the diameter of the parent droplets as you increased the height of the drop? How do the spines compare from the different heights?
29 Lab 2: Multiple Droplets Label a long piece of butcher paper (2-3 meters in length) as shown below. Keep your drops in the correct area of the paper. Multiple Drops Group Members To do the lab, put on your goggles and hold the dropper bottle upside down so that the end of it is 25 cm from the paper. GENTLY squeeze the bottle so that ONE drop of blood is released and lands in the correct location on your paper. The drop should NOT hit the meterstick. Without moving your hand, release ONE more drop onto the first drop at that height. If you make a mistake, wipe it off with a paper towel and try it again. Continue making drops of blood on your paper so you have three sets for each height. When you are done, analyze your results and answer the questions on your worksheet. Clean up your area and put away your materials before you leave class.
30 Lab 2 Questions Use your results to answer these questions. What happened when one drop landed on top of another one? What did you notice about the diameter of the parent droplets as you increased the height of the drop? What do you notice about the diameter of the satellite spatter as you increased the height of the drop?
31 Lab 3: Motion Droplets During this lab, you will see how motion affects the size and shape of the droplets and spines. You will need a long piece of butcher paper (4-5 meters in length) and tape to secure it to the floor. You will also need safety goggles. To do the lab, you will need to hold the dropper bottle upside down so that your hand is out and away from your body (waist level), but is still over the paper. Start off walking at a SLOW WALKING RATE along the paper strip from one end to the other and GENTLY squeeze the bottle as you walk so that blood is released ONE DROP at a time. Be sure that all the drops land on your paper strip. Repeat this procedure using a NORMAL WALKING RATE and a FAST WALKING RATE. Walking Direction Miss the paper? Use a paper towel to wipe it off the floor! When you are done, analyze your results and answer the questions on your worksheet. Clean up your area and put away your materials before you leave class.
32 Lab 3 Questions Use your results to answer these questions. Draw a sketch of the droplets showing the size, shape, and/or distance between them at each speed in the chart below. What did you notice about the shape of the droplets as you increased your walking speed? What did you notice about the spines as you increased your walking speed? What did you notice about the distance between the droplets as you increased your walking speed?
33 Which of the three blood droplets shown would have been created by a wound in the lower part of the leg? Explain. If you have a blood droplet as shown at left, what does it tell you? Explain. If you find a trail of blood with droplets that are round and close together, what could this mean?
34 Forensic Science Presentation developed by T. Trimpe
35 Biology of Hair Hair is composed of the protein keratin, which is also the primary component of finger and toe nails. Hair is produced from a structure called the hair follicle. Humans develop hair follicles during fetal development, and no new follicles are produced after birth. Hair color is mostly the result of pigments, which are chemical compounds that reflect certain wavelengths of visible light. Hair shape (round or oval) and texture (curly or straight) is influenced heavily by genes. The physical appearance of hair can be affected by nutritional status and intentional alteration (heat curling, perms, straightening, etc.). The body area (head, arm, leg, back, etc.) from which a hair originated can be determined by the sample s length, shape, size, color, and other physical characteristics. In order to test hair evidence for DNA, the root must be present. Sources: &
36 Hair Structure Hair is composed of three principal parts: Cuticle outer coating composed of overlapping scales Cortex protein-rich structure around the medulla that contains pigment Medulla central core (may be absent) The structure of hair has been compared to that of a pencil with the medulla being the lead, the cortex being the wood and the cuticle being the paint on the outside.
37 Hair Structure Cuticle The cuticle varies in: Its scales, How many there are per centimeter, How much they overlap, Their overall shape, and How much they protrude from the surface Its thickness, and Whether or not it contains pigment. Characteristics of the cuticle may be important in distinguishing between hairs of different species but are often not useful in distinguishing between different people. Info: Image:
38 Hair Structure Cortex The cortex varies in: Thickness Texture Color Distribution of the cortex is perhaps the most important component in determining from which individual a human hair may have come. Microscopic examination can also reveal the condition and shape of the root and tip. Info: Image:
39 Hair Structure Medulla The medulla may vary in: Thickness Continuity - one continuous structure or broken into pieces Opacity - how much light is able to pass through it It may also be absent in some species. Like the cuticle, the medulla can be important for distinguishing between hairs of different species, but often does not lend much important information to the differentiation between hairs from different people.
40 Fiber Evidence A fiber is the smallest unit of a textile material that has a length many times greater than its diameter. A fiber can be spun with other fibers to form a yarn that can be woven or knitted to form a fabric. The type and length of fiber used, the type of spinning method, and the type of fabric construction all affect the transfer of fibers and the significance of fiber associations. This becomes very important when there is a possibility of fiber transfer between a suspect and a victim during the commission of a crime. Matching unique fibers on the clothing of a victim to fibers on a suspect s clothing can be very helpful to an investigation, whereas the matching of common fibers such as white cotton or blue denim fibers would be less helpful. The discovery of cross transfers and multiple fiber transfers between the suspect's clothing and the victim's clothing dramatically increases the likelihood that these two individuals had physical contact.
41 Natural Fibers Many different natural fibers that come from plants and animals are used in the production of fabric. Cotton fibers are the plant fibers most commonly used in textile materials The animal fiber most frequently used in the production of textile materials is wool, and the most common wool fibers originate from sheep.
42 Synthetic Fibers More than half of all fibers used in the production of textile materials are synthetic or man-made. Nylon, rayon, and polyester are all examples of synthetic fibers. Cross-section of a man-made fiber Fibers under a microscope Images:
43 It s time to examine some hairs and fibers!
44 Directions: Hair & Fiber Identification Lab Your team will need to use a microscope to document all the hairs and fibers in your set. Write the name of the hair or fiber on the line and then draw what you see under medium or high power. Be sure to indicate the power of magnification! Add a description that highlights the unique characteristics of each hair and fiber sample. Pay attention to details to help you identify samples during the Hair & Fiber Challenge activity.
45 Can you identify the animal hairs shown? Think About It (1) In which samples are we viewing the cuticle? How do they compare? (2) In which samples are we viewing the medulla? How do they compare? (3) What characteristics can be used to identify hair samples?
46 Can you identify the types of fibers shown? Think About It (1) Which samples are natural fibers? (2) Which samples are synthetic fibers? (3) What characteristics can be used to identify fiber samples?
47 Answer Keys
48 Types of Animal Hairs - Key A Cat B Horse C Pig D Human G E Deer F Dog Rabbit H Rat I Human
49 Types of Fibers - Key Acrylic Yarn Cotton Yarn Nylon Rope Polyester Yarn Rayon Rope Wool Yarn