Background Information 1 What is Crime Scene Investigation

Background Information 1

What is Crime Scene Investigation? The application of natural sciences and technologies to matters of law. The word forensic is derived from the Latin “forensis” meaning forum, a public place where, in Roman times, senators and others debated and held judicial proceedings.

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 or Representative (if necessary) § Photographer and/or Field Evidence Technician § Lab Experts pathologist serologist DNA expert toxicologist forensic odontologist forensic anthropologist forensic psychologist forensic entomologist firearm examiner bomb and arson expert document and handwriting experts fingerprint expert 3

Types of Physical Evidence Biological Chemical Physical Miscellaneous 4

Biological Evidence Biological— Blood, semen, saliva, sweat, tears, hair, bone, tissues, urine, feces, animal material, insects, bacterial, fungal, and botanical. 5

People of Historical Significance In the 1900’s, Karl Landsteiner, an Australian scientist, after mixing blood cells and serum found that only certain combinations of blood was compatible. Prior to this discovery, a blood transfusion was usually fatal! 6

People of Historical Significance Edmond Locard (1877 -1966) § French professor § Considered the Father of Criminalistics. § Built the world’s first forensic laboratory in France in 1910. § Locard Exchange Principle: “Whenever two objects come into contact with each other, traces of each are exchanged. ” 7

A Tidbit More • From 1950 to the late 1980’s, forensic serology was the most important part of lab procedures. With the development of DNA techniques, more time, money, and significance was placed in developing DNA labs. However, with limited funds and the time required for DNA testing, most labs still used many of the basic serology testing procedures. 8

Serology is the examination and analysis of body fluids. A forensic serologist may analyze a variety of body fluids including saliva, semen, urine, and blood. 9

Investigating Blood Evidence 10

Blood Evidence • Class evidence for blood would include blood type. If you can determine the DNA you would have individual evidence. • Blood stain patterns are considered circumstantial evidence in a court room. Experts could argue many points including direction of travel, height of the perpetrator, position of the victim, left/right hand, whether the body was moved, etc. 11

Blood Terminology • ABO blood groups—based on having an A, B, both or no antigens on red blood cells • Antibody—a substance that reacts with an antigen • Antigen—a substance that can stimulate the body to make antibodies. Certain antigens (proteins) found in the plasma of the red blood cell’s membrane account for blood type. • Agglutination—clumping of red blood cells; will result if blood types with different antigens are mixed • Rh factor—may be present on red blood cells; positive if present and negative if not 12

Blood • An antibody and an antigen of different types will agglutinate, or clump, when mixed together. • The significance of the evidence depends on a characteristic’s relative occurrence in the population. 13

Distribution of Blood Types in the U. S. Population TYPE FREQUENCY CAN RECEIVE CAN DONATE BLOOD FROM BLOOD TO 0+ 37% 45% 84% 0 - 7% 7% 100% A+ 35% 85% 37% A- 6% 13% 44% B+ 9% 56% 12% B- 2% 9% 15% AB+ 3% 100% 3% AB- 1% 16% 4% 15

What Can Blood Drops Reveal? Safety v. In this lab, you will work with artificial or aseptic blood samples obtained from your teacher. v. Handle and dispose of the samples as instructed by the testing kit or your teacher. v. Be sure to keep your hands away from your eyes and face in the science lab. v Remember to wash your hands thoroughly before and after completing the lab procedure. 26

The Problem: What Can Blood Drops Reveal? Some school property was vandalized, and a few drops of blood were found at the scene of the crime. The detectives investigating the incident think that the blood came from the perpetrator of the crime, who apparently was slightly injured during the vandalism. The detectives have gathered a group of suspects who were all on school property when the crime was committed. However, the only hard evidence is the blood found at the scene. The detectives want to rule out as many of the innocent suspects as possible on the basis of the blood evidence. In this lab, you will act as a forensic serologist, analyzing a sample of blood from a suspect to determine the blood type. 17

Student Investigation/Procedures • Work in pairs to analyze four suspects’ blood samples. Record results in Part 1 of the Analysis Worksheet. • When finished, ask your teacher for the unknown sample found at the crime scene. • Analyze the unknown sample. Record results in Part 2 of the Analysis Worksheet. • Compare the results of the known suspects and unknown suspect(s). • Based on your results, narrow the field of suspects. 18

Agglutination- Clumping 19

Materials Needed Materials- Per group 5 Blood typing slides Magnifying glass White paper 2 pair of Rubber Gloves 15 Plastic toothpicks Clear plastic trays Alternative blood stained cloth Shared Materials 4 Known blood samples 1 Unknown blood sample Simulated Anti-A Serum Simulated Anti-B Serum Simulated Anti- Rh Serum 33

Cleanup and Disposal 1. Put all materials back into the zip lock bag for disposal. 2. Wipe down your work surface with the wet paper towel/ toilettes when finished. 21

Resource http: //nobleprize. org/educational_games/medi cine/landsteiner 22

Blood Types Antibody Can Give Can Get Blood From Type Antigen A A B A, AB O, A B B A B, AB O, B AB A and B Neither A nor B AB A, B, O, AB O Neither A nor B A and B A, B, O, AB O Blood To 23

Making Biology Connections Human Blood Types Genotypes Surface Molecules Phenotypes l. A or l. Ali A A l. B or l. Bli B B l. Al. B A and B AB ii None O 24

Debrief NOS/SI NOS: Integrated Theme SI: Integrated Theme • Explain that scientific knowledge is tentative due to new evidence or new interpretation. • Distinguish observations from inferences, explain that inferences should be based on observations, and explain that the development of scientific knowledge involves both observations and inferences. • Explain that scientific knowledge should be based on empirical data. • Explain that scientific investigations all begin with a question, but do not necessarily test a hypothesis. • Explain that inquiry procedures are guided by the question asked. • Explain that research conclusions must be consistent with the data collected. • Explain that scientific data are not the same as scientific evidence. • Explain that explanations are developed from a combination of collected data and what is already known. 25

Modifications • This lesson is a modification of Lab 9 from the Forensic and Biotechnology supplement in your Glencoe Biology Bundle. • This lesson could be extended to a two day lab. Day One would be a pre-lab/intro and Day Two would be the investigations. • For students who require more guidance in the lab (for safety or other reasons), have he/she paired with a student who needs less guidance. • Reduce the number of test ran by a pair. • Use Chapter 12. 3 ‘Inside Story’ for a visual representation of ABO blood cell types, their phenotypes and genotypes. 26

Extensions • This lesson could be extended to a two day lab. Day One would be an Introduction to Forensics and Day Two would be the investigations. • Blood testing kits come with additional test or activities besides just blood typing. Some kits may come with Blood Cell Count activity, others may have students use the microscope to count the number of white blood cells and red blood cells in one drop of simulated blood. • Other types of extensions are calculating blood splatter patterns and determining if the stain is an animal or human blood. • If students are interested in Forensic science, they can investigate the different careers associate with forensics. 27