Class Name, Instructor Name Lasley & Guskos, Criminal Investigation: An Illustrated Case Study Approach 1ed Chapter 8 INVESTIGATION AND THE FORENSIC SCIENCES Class Name, Instructor Name Date, Semester

CHAPTER OBJECTIVES Explain what is meant by the term forensic sciences Describe the role of the crime laboratory Describe the various sections making up a crime laboratory Describe how DNA analysis is used in criminal investigation Be familiar with types of forensic sciences used outside the crime lab

Types of Testing in the Lab

Explain what is meant by the term forensic sciences Learning Objectives After this lecture, you should be able to complete the following Learning Outcomes Explain what is meant by the term forensic sciences

History of Crime in America FORENSIC SCIENCE Application of science to the law 5 5

Frye & Daubert Tests Frye test: Frye v. US (1923) Any science is recognized by a court as legitimate if it is accepted by a relevant scientific discipline (general acceptance standard) Daubert test: For a court to recognize forensic science it must: Be testable Establish error rates Peer reviewed Accepted by experts (scientific evidence standard)

Forensic Scientists FORENSIC SCIENTISTS CRIMINALISTS Perform analysis of crime scenes Work for the prosecution and can work privately for the defense 7 7

Describe the various sections making up a crime laboratory Learning Objectives After this lecture, you should be able to complete the following Learning Outcomes Describe the various sections making up a crime laboratory

Recognized subdisciplines of forensic sciences General toxicology Firearms/tool marks Questioned documents Trace evidence Controlled substances Fire debris/arson Impression evidence Biological/serological screening Blood pattern analysis Crime scene investigations Medico-legal death investigation Digital evidence

Controlled Substance Testing

Describe the role of the crime laboratory Learning Objectives After this lecture, you should be able to complete the following Learning Outcomes Describe the role of the crime laboratory

Crime Lab Goals and Achievement Identify physical evidence & determine origin Search for and locate evidence Perform a presumptive test Perform confirmatory test Report the results

Tests/Analytical Methods Microscopic Analysis Color Tests Chromatography Mass Spectrometry Biological Tests

Biological Testing

Crime Lab Sections Toxicology—affects, both physical and behavioral that poisons have on the body Fingerprint identification—processing of fingerprints, use of AFIS and IAFIS to match prints, ACE-V (analysis, compares, evaluates, verification) Serology—analyses blood stains and performs blood testing (blood types O, A, B, AB) Arson and Explosives—fire and explosive evidence, examine burnt, destroyed objects from explosions

Crime Lab Sections Firearms and Tool Marks—examinations to determine class and individual characteristics of tools and firearms, NIBIN Trace evidence—hairs, fibers, glass fragments, paint chips, and other materials in minute sizes are analyzed in this section Questioned documents—false documents that assist in financial crimes, identify paper, inks, writing styles, etc.

Individual Characteristics

Describe how DNA analysis is used in criminal investigation Learning Objectives After this lecture, you should be able to complete the following Learning Outcomes Describe how DNA analysis is used in criminal investigation

2 Types of DNA Nucleic DNA, derived from a cell containing nucleus and can be used as individual evidence Mitochondrial DNA, class evidence, most useful in exclusion of suspects nDNA mtDNA

Genetic Fingerprint nDNA Considered a genetic fingerprint which contains codes and instructions for the body to create and sustain itself 20 20

DNA Evidence DNA Recovery White blood cells Sperm Epithelial cells Bone marrow Tooth pulp Follicle tags

Sample DNA

Identifying the DNA Fingerprint Codes and Symbols Adenine “A” Thymine “T” Guanine “G” Cytosine “C”

Analysis methods nDNA: PCR is the method of choice Removal of DNA strands from cells, coding can begin once separated mtDNA: An addition to the nDNA method; the shaft region of all body hairs is tested and can yield results without skin cells attached

CODIS & The future of DNA FBI DNA database system Combined DNA Index System Profiles of adults and juveniles The Innocence Project (1992) DNA exonerated some inmates based on this scientific method

Be familiar with types of forensic sciences used outside the crime lab Learning Objectives After this lecture, you should be able to complete the following Learning Outcomes Be familiar with types of forensic sciences used outside the crime lab

Other Forensic Sciences Forensic Pathology (cause of death) Forensic Anthropology (identify human remains) Forensic Entomology (study of insects) Forensic Psychology & Psychiatry (mental abilities & personality traits) Digital Forensic Science (electronic crimes)

support of investigations, legal proceedings, and trials. CHAPTER SUMMARY Forensic science is the application of science to the law. Although virtually any forensic science can be applied to the practice of investigation, the law dictates which forensic sciences can be used to present evidence in a legal proceeding. Crime labs conduct scientific analyses on physical evidence obtained from crime scenes, victims, and suspects. Many of the functions carried out by crime labs include performing presumptive and confirmatory testing of suspected, yet unknown, illegal substances and materials. Specialized testing is also conducted to class and individualize evidence in support of investigations, legal proceedings, and trials. Crime lab sections include toxicology, fingerprint ID, serology, arson and explosives, firearms and tool marks, trace evidence, questioned documents, and DNA analysis.

CHAPTER SUMMARY DNA can be acquired from a variety of sources within the human body, including white blood cells, skin cells (nDNA), and hair (mtDNA). In the analysis of nDNA, which can be individualized in the form of a human genetic fingerprint, specific characteristics of locations on DNA strands are compared for differences. This generates a DNA profile, which can be used to positively identify offenders or exclude suspects. mDNA, which is obtained from hair or the mitochondria of cells, cannot be used to positively identify offenders, but is useful for excluding suspects. Branches of the forensic sciences practiced by experts outside the crime lab include forensic pathology, forensic anthropology, forensic psychology and psychiatry, forensic entomology, and digital forensic science.