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Forensic Science SFS1. Students will recognize and classify various types of evidence in relation to the definition and scope of Forensic Science. a. Compare.

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Presentation on theme: "Forensic Science SFS1. Students will recognize and classify various types of evidence in relation to the definition and scope of Forensic Science. a. Compare."— Presentation transcript:

1 Forensic Science SFS1. Students will recognize and classify various types of evidence in relation to the definition and scope of Forensic Science. a. Compare and contrast the history of scientific forensic techniques used in collecting and submitting evidence for admissibility in court (e.g. Locard’s Exchange Principle, Frye standard, Daubert ruling).

2 ESSENTIAL QUESTIONS 1.What is forensic science? 2.What is evidence and how is it used by forensic scientists? 3.What are the characteristics of a typical crime lab? 4.Which historical forensic scientists laid the ground work for modern forensic science? 5.What is the importance of Locard’s Exchange Principle?

3 ESSENTIAL QUESTIONS 6.What is the basic methodology used by forensic scientists? 7.What are the steps that must be followed in the pursuit of justice? 8.What is the importance of the Federal Rules of Evidence? 9.What is the importance of the Frye Standard? 10.What is the importance of the Daubert Ruling?

4 Sequence of Events 1)Introduction to Forensic Science and the Law 2)The Crime Scene 3)Fingerprint Analysis 4)Hair and Fiber Analysis 5)Soil and Glass Analysis 6)Handwriting and Document Analysis 7)Forensic Pathology 8)Forensic Toxicology 9)Forensic Serology and DNA Analysis 10)Firearms, Toolmarks and Impressions 11)Arson and Explosives

5 Forensic Science is… the application of science to those criminal and civil laws that are enforced in a criminal justice system. Criminalistics is… the examination of physical evidence

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7 Forensic scientists use crime labs to help them examine… EVIDENCE – anything that tends to establish or disprove a fact documents testimony objects

8 Forensic Specialties  Anthropology (human remains)  Psychiatry (mind)  Odontology (bitemarks)  Engineering (structural failures)  Computer Technology (data recovery)  Pathology (death)  Geology (earth)

9 More Specialties  Environmental Science (human effect on earth)  Entomology (insects)  Palynology (pollen & spores)  Polygraphy (lie detector)  Voiceprint Analysis

10 A forensic scientist’s main job is to study the different types of evidence found at a crime scene, but s/he must also testify as an expert witness, perform scientific research and train others.

11 Crime Laboratories There are ~ 350 crime labs in US –Federal, state, county, and municipal (local) –Most function as part of a police department –Others fall under direction of the prosecutor or district attorney’s office –Some work with labs of the medical examiner or coroner –A few are affiliated with universities or exist as independent agencies in government

12 Most labs are maintained by states for regional areas –GBI has 7 regional labs; –Eastern Regional Lab is located in Augusta and serves 15 counties

13 There is NO national system of forensic laboratories So… there is little organization and consistency among US forensic labs

14 Crime Lab Departments Physical Science –Chemistry (drug analysis) * –Trace Evidence (hair, fiber, soil, glass, paint, GSR) Biology (blood, DNA, cells) * Firearms (ballistics, toolmarks) * Questioned Documents ( handwriting, documents, impressions) Photography Toxicology (drugs/alcohol/poisons in bio. samples) * Fingerprints Pathology (manner/cause of death)

15 Crime Lab Statistics State funded labs have a budget of ~$1 bil. Average salary for an analyst is ~$50k/yr ~90% of all analyses are for controlled substance ID ~20% of cases are backlogged (>30 days) –most are DNA analyses Oldest lab in world is in Lyons, France (1910) Oldest lab in US is LAPD (1923)

16 Federal Forensics Labs Federal Bureau of Investigation –Largest in the world –Located in Quantico, VA –Operated by the Department of Justice (DOJ) Drug Enforcement Agency –Drug-related crimes –21 regional divisions –Operated by the DOJ

17 Federal Forensics Labs Bureau of Alcohol, Tobacco, Firearms, and Explosives –Crimes involving alcohol, tobacco, firearms, explosives, suspected arson, and organized crime –National Laboratory Center located in Beltsville, MD –Operated by the DOJ

18 Federal Forensics Labs United States Postal Inspection Service –Crimes involving the mail –Located in Dulles, VA –Operated by the United States Postal Service United States Fish & Wildlife Service –Crimes against wildlife –Located in Ashland, OR –Operated by the Department of the Interior

19 Orfila (1814) –Father of forensic toxicology. –First treatise on detection of poisons and their effects on animals. Bertillon (1879) –Father of criminal identification –Developed the science of anthropometry—the taking of body measurements as a means of distinguishing people. Galton (1892) –First statistical proof supporting the uniqueness of fingerprints. Gross (1893) –Father of criminalistics –First treatise describing the application of science to the field of criminal investigation Founding Scientists

20 Locard (1910) –Father of forensic science. –Developed the idea of cross-transfer of evidence Osborn (1910) –Developed the fundamental principles of document examination. Lattes (1915) –Developed a procedure to ID blood groups from dried bloodstains. Goddard (1925) –Refined the techniques of bullet ID with the comparison microscope. McCrone (1977) –Perfected the use of the microscope in forensic investigation.

21 Methodology Locard’s Exchange Principle “Whenever two objects come into contact, there is always a transfer of material. The methods of detection may not be sensitive enough to demonstrate this, or the decay rate may be so rapid that all of the evidence of transfer has vanished after a given time. Nonetheless, the transfer has taken place.”

22 Methodology The Scientific Method 1.Observe a problem or questioned evidence and collect objective data 2.Consider a hypothesis or possible solution to the problem based on observation. This step requires inductive reasoning (specific  general), experience, and imagination.

23 Methodology 3.Examine, test, and analyze to support or refute the hypothesis. 4.Use deductive reasoning (general  specific) to make a determination as to the significance of the evidence.

24 Methodology 5.Evaluate and verify all evidence. This step is especially critical to a forensic scientist because someone’s liberty can be at stake. 6.Develop a theory or opinion that is able to stand up to scientific and legal scrutiny.

25 Criminal Justice and the Law US Constitution is the supreme body of laws that trumps all Statutory Law (legislation) –Enacted by a governmental body or agency having the power to make laws (such as Congress) Common Law (case law) –Made by judges –Precedents allow for consistency and predictability in how the law is applied

26 Civil Law (code law) –Collection of codified statutes –Precedents are given less weight –Deals with relationships between individuals –More concerned with assigning blame than with establishing intent –“Preponderance of evidence” is required to convict

27 Criminal Law (penal law) –Body of rules that defines conduct prohibited by the state and assigns punishment for breach –Punishments are related to the “guilty act” and the “guilty mind” –Distinguished between “major” and “minor” crimes –“Beyond a reasonable doubt” is required to convict

28 Steps in Pursuing Justice Once a crime is committed and discovered… –A suspect may be identified –Police investigate what may have happened –Information is collected –Crime scene is documented and searched for evidence –Info is assembled into a report for the prosecutor –Investigation ensues –If enough evidence can establish probable cause, then an arrest warrant is issued

29 After a suspect has been arrested… –S/he is booked, fingerprinted, photographed, and informed of his/her Miranda rights –Brought before a judge within 48 hrs for arraignment to hear charges and enter a plea

30 After a defendant’s plea is made… –A preliminary hearing is conducted before a judge This is to determine whether there is enough evidence to proceed to a trial Probable cause must be established –Federal gov’t and some states may use a grand jury for felony cases Defendant is not entitled to counsel

31 Pleading “not guilty by reason of insanity”… –Requires the defendant to prove the inability to “know right from wrong” at the time of the commission of the crime –It removes the requirement to demonstrate intent

32 A person is presumed innocent until proven guilty –The burden of proof rests with the prosecution –Only 50% of all arrests lead to conviction –Only 25% of all convictions are sentenced to 1+ years in prison

33 Plea bargaining can reduce the burden on the court by allowing a defendant to plead guilty to a lesser charge and avoid a trial –90% of all cases are “pleaded down”

34 Types of Crimes A broken law is called a violation. INFRACTION “regulatory offenses” –Least serious class of crime –Can be proceeded against without the right to a jury trial and/or indictment –Punishable by fines –Include traffic tickets/violations, jaywalking, littering, disturbing the peace

35 MISDEMEANOR –More serious class of crime than infraction –Punishable by 1 year or less in prison, house- arrest, probation, community service… –Include petty theft, prostitution, public intoxication, disorderly conduct, trespassing…

36 FELONY –Most serious class of crime –Punishable by more than 1 year in prison or by death –Include aggravated assault/battery, arson, burglary, grand theft, robbery, murder, rape…

37 Federal Rules of Evidence (1975) To be acceptable in court, evidence must be RELEVANT; that is, it should be both MATERIAL and PROBATIVE. –Material evidence has some logical connection to a fact of consequence to the outcome of a case –Probative evidence can prove or disprove legal elements of the case

38 The forensic scientist, or expert witness, has an obligation to be an advocate for the truth, and should not take sides for either the defense or prosecution. The person who presents scientific evidence must establish credibility via credentials, background, and experience.

39 The Frye standard (Frye vs. US, 1923) Frye was convicted of murder. On appeal, defendant’s counsel offered an expert witness to testify to the result of a deception (pre-polygraph) test, claiming that during the first trial, the testimony was not accepted. SCOTUS let the conviction stand and stated that scientific evidence must have gained “general acceptance” to be accepted in court –At that time, the deception test was not “generally accepted”…

40 The Frye standard –Commonly called the “general acceptance” test –Dictates that scientific evidence is admissible at trial only if the methodology or science is “generally accepted” in the field of study –Only applies to new science/technologies

41 The Daubert standard (Daubert vs. Merrell Dow Pharmaceuticals, 1993) Daubert family sued Dow claiming that children’s birth defects had been caused by mother’s prescription drugs The trial court decided that evidence did not meet the Frye Standard In appeals, SCOTUS decided that the Frye Standard was no longer appropriate because of technological sophistication

42 The Daubert Ruling –The judge is the “gatekeeper” –Applies to federal courts –Endorses the classical definition of the Scientific Method Hypothesis testing Estimates of error rates Peer-reviewed publication General acceptance Technique standardization


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