1. 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

2. 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

3. Types of Testing in the Lab

4. 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

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

6. 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)

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

8. 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

9. 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

10. Controlled Substance Testing

11. 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

12. 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

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

14. Biological Testing

15. 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

16. 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.

17. Individual Characteristics

18. 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

19. 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

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

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

22. Sample DNA

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

24. 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

25. 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

26. 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

27. 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)

28. 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.

29. 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.