1 Chapter 18 Scientific Evidence

2 The Use of Scientific Evidence Even though scientific evidence is not infallible, it could contribute to an investigation by: Even though scientific evidence is not infallible, it could contribute to an investigation by: Providing a lead or leads to head a criminal investigation in the right direction. Providing a lead or leads to head a criminal investigation in the right direction. Providing information eliminating a suspect as the person who committed the crime being investigated. Providing information eliminating a suspect as the person who committed the crime being investigated. Proving corpus delicti, or proof that a crime was committed. Proving corpus delicti, or proof that a crime was committed.

3 Providing the independent corroborative evidence necessary to support a confession. Providing the independent corroborative evidence necessary to support a confession. Establishing a link between the crime scene and the suspect or between the suspect and the victim of the crime. Establishing a link between the crime scene and the suspect or between the suspect and the victim of the crime. Proving one of the essential elements of the crime being investigated. Proving one of the essential elements of the crime being investigated. Affirming or disproving an alibi. Affirming or disproving an alibi.

4 Establishing the innocence of people not involved in the crime. Establishing the innocence of people not involved in the crime. Encouraging or inducing a person to make a confession or an incriminating admission when the person is confronted with scientific evidence that incriminates them. Encouraging or inducing a person to make a confession or an incriminating admission when the person is confronted with scientific evidence that incriminates them. Providing reasonable suspicion or probable cause. Providing reasonable suspicion or probable cause. Building such strong cases against defendants that the number of guilty pleas are increased, clearing court calendars and permitting faster trials of contested cases. Building such strong cases against defendants that the number of guilty pleas are increased, clearing court calendars and permitting faster trials of contested cases.

5 What Is Scientific Evidence? Scientific evidence is most often presented in court by an expert witness testifying on expert opinions. It also includes expert testimony that goes beyond science. The scientific expert is frequently called upon to interpret results and draw conclusions about what results mean in the case being tried.

6 Courts traditionally use one of these rules for the admissibility of scientific evidence: The Frye Test The Frye Test Frye v. United States (1928) 293 F Frye v. United States (1928) 293 F The Frye Test Plus or KELLY- Frye test The Frye Test Plus or KELLY- Frye test People v. Kelly (1976) 17 Cal.3d 24 People v. Kelly (1976) 17 Cal.3d 24 Daubert Test Daubert Test Daubert v. Merrell-Dow Pharmaceuticals, Inc. 509 U.S. 579, 113 S.Ct (1993). Daubert v. Merrell-Dow Pharmaceuticals, Inc. 509 U.S. 579, 113 S.Ct (1993).

7 Frye Standard, Frye v. U.S. 293 F (D.C. Cir. 1923) Essentially, for the results of a scientific technique to be admissible, the technique must be sufficiently established to have gained general acceptance in its particular field. Essentially, for the results of a scientific technique to be admissible, the technique must be sufficiently established to have gained general acceptance in its particular field. This is referred to as the "general acceptance" test by the scientific community. This is referred to as the "general acceptance" test by the scientific community.

8 Kelly-Frye Hearings Kelly-Frye hearings are preliminary hearings in which the judge determines whether or not to permit particular scientific evidence to be presented to the jury during trial. Kelly-Frye hearings are preliminary hearings in which the judge determines whether or not to permit particular scientific evidence to be presented to the jury during trial. In a typical Kelly-Frye hearing, both the proponent and the opponent of the scientific technique bring in a parade of scientific experts and present their best arguments for or against the admissibility of the particular scientific evidence involved. In a typical Kelly-Frye hearing, both the proponent and the opponent of the scientific technique bring in a parade of scientific experts and present their best arguments for or against the admissibility of the particular scientific evidence involved. California uses the Kelly-Frye Test California uses the Kelly-Frye Test

9 The Daubert Test The court suggested the trial court consider various factors to assess scientific validity The court suggested the trial court consider various factors to assess scientific validity Has the theory been tested? Has the theory been tested? Has it been subjected to peer review by other scientists? Has it been subjected to peer review by other scientists? What is the theory’s or technique’s known or potential rate of error? What is the theory’s or technique’s known or potential rate of error? Do standards controlling the application of the theory or technique? Do standards controlling the application of the theory or technique? Is the theory or technique generally accepted? Is the theory or technique generally accepted?

10 Daubert v. Merrell Dow (1993) The Court “REJECTED” the more basic Frye test of “general acceptance” in the scientific community. The Court “REJECTED” the more basic Frye test of “general acceptance” in the scientific community. Daubert requires an independent judicial assessment of reliability. Daubert requires an independent judicial assessment of reliability. This test requires special pretrial hearings for scientific evidence and special procedures on discovery. This test requires special pretrial hearings for scientific evidence and special procedures on discovery. This is a more stringent test that requires knowledge of Type I and Type II error rates, as well as validity and reliability coefficients. This is a more stringent test that requires knowledge of Type I and Type II error rates, as well as validity and reliability coefficients.

11 Daubert test requires (federal) judges to ascertain the following: (1) Whether the theory or technique is capable of being or has been tested; (1) Whether the theory or technique is capable of being or has been tested; (2) Whether it has been subjected to peer review and publication; (2) Whether it has been subjected to peer review and publication; (3) The known or potential rate of error in using a particular scientific technique and the standards controlling the technique's operation; and (3) The known or potential rate of error in using a particular scientific technique and the standards controlling the technique's operation; and (4) Whether the theory or technique is generally accepted in the particular scientific field. (4) Whether the theory or technique is generally accepted in the particular scientific field.

12 Frye vs. Daubert? In terms of DNA admissibility, the two major differences between Frye and Daubert are: In terms of DNA admissibility, the two major differences between Frye and Daubert are: (1) Daubert requires a consideration of error rates, whereas Frye typically does not. (1) Daubert requires a consideration of error rates, whereas Frye typically does not. (2) In Frye jurisdictions, the debate over how to calculate the significance of a genetic match goes toward the admissibility of the evidence, whereas in Daubert jurisdictions, it goes toward the weight. (2) In Frye jurisdictions, the debate over how to calculate the significance of a genetic match goes toward the admissibility of the evidence, whereas in Daubert jurisdictions, it goes toward the weight.

13 Judicial Role in Daubert The essence of Daubert is that the Supreme Court has deputized federal district judges as "gatekeepers," authorizing them to exercise broad discretion to exclude whatever evidence they deem to not meet scientific standards of admissibility. The essence of Daubert is that the Supreme Court has deputized federal district judges as "gatekeepers," authorizing them to exercise broad discretion to exclude whatever evidence they deem to not meet scientific standards of admissibility.

14 State vs. Federal States can “choose” between the tests and decide which to use as their standard. States can “choose” between the tests and decide which to use as their standard. Findings in a 2006 study showed that many states use parts of the Daubert test but not all. Findings in a 2006 study showed that many states use parts of the Daubert test but not all. The Federal Courts must use Daubert. The Federal Courts must use Daubert.

15 DNA Genetic Profiling Deoxyribonucleic acid (DNA) testing has become an important forensic tool for linking suspects to a crime. Deoxyribonucleic acid (DNA) testing has become an important forensic tool for linking suspects to a crime. Equally importantly, DNA testing has made it possible to eliminate a suspect in a crime, sometimes even after the suspect has been convicted of that crime (exculpatory evidence). Equally importantly, DNA testing has made it possible to eliminate a suspect in a crime, sometimes even after the suspect has been convicted of that crime (exculpatory evidence). DNA genetic profiling has received such wide acceptance among criminal justice professionals that it is frequently called genetic fingerprinting. DNA genetic profiling has received such wide acceptance among criminal justice professionals that it is frequently called genetic fingerprinting.

16 DNA Genetic Profiling (Cont.) Locus points : base pairs that vary from one individual to the next can be located. Locus points : base pairs that vary from one individual to the next can be located. For example, where eye color is determined, base pairs will join in a sequence that is repeated. For example, where eye color is determined, base pairs will join in a sequence that is repeated. Measuring the size of a repetitive sequence of base pairs at many such locations gives a fingerprint-like picture of the DNA chain, since at these locations, the sequence of base pairs varies among different individuals. Measuring the size of a repetitive sequence of base pairs at many such locations gives a fingerprint-like picture of the DNA chain, since at these locations, the sequence of base pairs varies among different individuals.

17 The FBI Laboratory's Combined DNA Index System (CODIS) blends forensic science and computer technology into an effective tool for solving violent crimes. CODIS enables state and local crime laboratories to exchange and compare DNA profiles electronically, thereby linking serial violent crimes to each other and to known sex offenders. (A DNA profile is the set of genetic characteristics that result from forensic DNA analysis.) The FBI Laboratory's Combined DNA Index System (CODIS) blends forensic science and computer technology into an effective tool for solving violent crimes. CODIS enables state and local crime laboratories to exchange and compare DNA profiles electronically, thereby linking serial violent crimes to each other and to known sex offenders. (A DNA profile is the set of genetic characteristics that result from forensic DNA analysis.)

18 FBI’s Report on What Police Officers Need to Know about DNA pdf pdf pdf pdf Excellent resource for the Criminal Justice Student or Police Officer Excellent resource for the Criminal Justice Student or Police Officer

19 Cases where DNA Evidence Did Not Carry the Burden of Proof O.J. Simpson murder trial O.J. Simpson murder trial Former Teamster Union President, James Hoffa’s disappearance Former Teamster Union President, James Hoffa’s disappearance See text for details See text for details

20 The Military and DNA The U.S. military services are currently asking families of service members to submit DNA samples for aid in identification of remains found (WWII and the Korean and Vietnam Wars). The U.S. military services are currently asking families of service members to submit DNA samples for aid in identification of remains found (WWII and the Korean and Vietnam Wars).

21 Other Ways of Using DNA to Identify Suspects Using close DNA matches Using close DNA matches Using animal DNA to link suspect to the crime scene Using animal DNA to link suspect to the crime scene

22 Forensic Entomology Entomology is the study of insects. Entomology is the study of insects. Forensic Entomology is used to determine the time since death on human cadavers and other facts surrounding the death such as location, placement, movement of the body, and information on the manner of death. Forensic Entomology is used to determine the time since death on human cadavers and other facts surrounding the death such as location, placement, movement of the body, and information on the manner of death. An estimate might be made at the crime scene based on lividity of the body or the advance of rigor mortis. An estimate might be made at the crime scene based on lividity of the body or the advance of rigor mortis. Lividity is the process of blood settlement within the body after death Lividity is the process of blood settlement within the body after death Rigor mortis is the stiffening of the body’s muscles occurring after death Rigor mortis is the stiffening of the body’s muscles occurring after death

23 Board of Forensic Entomology: Board of Forensic Entomology: entomology/ entomology/ entomology/ entomology/ International Forensic Entomology links: ent/forensic_entomology.html International Forensic Entomology links: ent/forensic_entomology.html ent/forensic_entomology.html ent/forensic_entomology.html

24 Forensic Odontology American Board of Forensic Odontology American Board of Forensic Odontology The objective of the Board is to establish, enhance, and revise, as necessary, standards of qualifications for those who practice forensic odontology, and to certify as qualified specialists those voluntary applicants who comply with the requirements of the Board. The objective of the Board is to establish, enhance, and revise, as necessary, standards of qualifications for those who practice forensic odontology, and to certify as qualified specialists those voluntary applicants who comply with the requirements of the Board. In this way, the Board aims to make available a practical and equitable system for readily identifying those persons professing to be specialists in forensic odontology who possess the requisite qualifications and competence. In this way, the Board aims to make available a practical and equitable system for readily identifying those persons professing to be specialists in forensic odontology who possess the requisite qualifications and competence.

25 The International Association for Identification IAI has grown into the most prestigious professional association of its kind in the world, with more than 5,000 members from the United States and many other countries. The advancement of forensic disciplines through education continues to be one of the top priorities of the Association. IAI has grown into the most prestigious professional association of its kind in the world, with more than 5,000 members from the United States and many other countries. The advancement of forensic disciplines through education continues to be one of the top priorities of the Association. THE IAI also certifies forensic experts in a variety of areas of expertise in Forensics. THE IAI also certifies forensic experts in a variety of areas of expertise in Forensics.

26 American Academy of Forensic Science As a professional society dedicated to the application of science to the law, the AAFS is committed to the promotion of education and the elevation of accuracy, precision, and specificity in the forensic sciences. As a professional society dedicated to the application of science to the law, the AAFS is committed to the promotion of education and the elevation of accuracy, precision, and specificity in the forensic sciences.

27 Ballistics Fingerprinting or Firearm Fingerprinting The rifling of the barrel of the gun leaves unique marks in the lead or steel of the bullet fragment. The rifling of the barrel of the gun leaves unique marks in the lead or steel of the bullet fragment. This technology is often called ballistic fingerprinting. This technology is often called ballistic fingerprinting. Technicians can then enter a digital image of the tiny markings into a computer data base called the National Integrated Ballistic Information Network. The computer then spits out likely matches which the examiners can then study further under a microscope. Technicians can then enter a digital image of the tiny markings into a computer data base called the National Integrated Ballistic Information Network. The computer then spits out likely matches which the examiners can then study further under a microscope. NIBIN on the web: NIBIN on the web: As 40% of criminal homicides are unsolved, identification of weapons used in these crimes is critical. As 40% of criminal homicides are unsolved, identification of weapons used in these crimes is critical.

28 Sources of Other Scientific Evidence Other scientific evidence used regularly in courts throughout the united states include: Other scientific evidence used regularly in courts throughout the united states include: Test for alcoholic intoxication Test for alcoholic intoxication Fire and explosive science evidence Fire and explosive science evidence Forensic pathology Forensic pathology Chemistry, toxicology, serology Chemistry, toxicology, serology Microanalysis Microanalysis Neutron activation analysis (NAA) Neutron activation analysis (NAA) Tests used in questioned documents Tests used in questioned documents Scientific detection of speeding Scientific detection of speeding Accident Reconstruction Accident Reconstruction Forensic odontology Forensic odontology Accident reconstruction techniques Accident reconstruction techniques Physical anthropology Physical anthropology

29 Sources for Collecting, Correlating, and Coordinating Evidence National Law Enforce Data Exchange (N- Dex) National Law Enforce Data Exchange (N- Dex) Terrorist Screening Center Terrorist Screening Center Combined DNA Index System (CODIS) Combined DNA Index System (CODIS) National Gang Threat Assessment and Database National Gang Threat Assessment and Database Hazardous Devices School Hazardous Devices School