introduction to forensic science presenting evidence in court
TRANSCRIPT
Introduction to Forensic Science
Presenting Evidence in Court
Forensic Scientist Skills
• An expert witness is an individual whom the court determines possesses knowledge relevant to the trial.
• The expert witness is called on to evaluate evidence based on specialized training and experience.
• The expert will then express an opinion as to the significance of the findings.
• Forensic Scientists are called upon to become experts so they can testify in court.
CRIMINALISTICS An Introduction to Forensic Science, 9/EBy Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
Law and Order
• This television show is more realistic since it portrays how courts work, not just criminal investigation and evidence collection and interpretation.
• Testimony of the forensic expert is what is regarded as admissible evidence.
• Evidence can be suppressed if it isn’t legally collected, with warrants etc.
Science in the Courts
• The rules and procedure for using scientific evidence in court have been developed in the USA
• Cases have been tried over the decades under tort law on the harm posed by exposure to toxic chemicals and carcinogens.
Science Testimony in Civil Cases
• Classification of carcinogenicity – Is there evidence to classify a substance
as a human carcinogen?– Is there evidence to classify a substance
as an animal carcinogen alone?– Can any conclusions be drawn at this
time?
Frye test (1923) vs. Daubert factors (1993)
• How is scientific evidence interpreted by the courts in the United States?
• Who is qualified to give testimony as an expert witness?
• How can “opinion” or “junk science” be kept out of the courts?
Frye Test
• In Frye v. U.S. (1923) expert testimony was admissible only if based upon techniques and procedure “generally accepted” in the scientific community.
• Experts were challenged during voir dire: this is a specific step in the pre-trial procedure to question experts (and jurors) about their qualifications and biases.
• “While courts will go a long way in admitting expert testimony deduced from well-recognized principles or discovery, the thing from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs.”
The Frye test was used for decades because:
• Those most qualified to assess the scientific method used will have a determinative voice.
• Consensus in a scientific community would promote uniformity of decisions.
• Frye’s conservative nature protects all parties: it created a mechanism for evaluating reliability in a consistent manner, since jurors tend to give undue weight to scientific evidence when presented by experts with impressive credentials.
Frye is Not Absolute
• The 1993 case of Daubert v. Merrell Dow Pharmaceutical, Inc., the U.S. Supreme Court asserted that the Frye standard is not an absolute prerequisite to the admissibility of scientific evidence.
CRIMINALISTICS An Introduction to Forensic Science, 9/EBy Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
Daubert v. Merrell Dow Pharmaceuticals (1993)
• Plaintiffs offered testimony from 8 experts alleging that Bendectin (an anti-nausea drug taken during pregnancy) was teratogenic (caused birth defects).
• The Supreme Court excluded the experts from testifying (ruled in favour of the defendants) and took this opportunity to enunciate a new standard for admissibility of expert evidence.
Daubert v. Merrell Dow Pharmaceuticals (1993)
• The Supreme Court upon reviewing Daubert held that the Federal Rules of Evidence 702 (1975) and not Frye were the criteria by which scientific evidence should be measured.
• The Federal Rules of Evidence, up until Daubert, did not hold the precedence that Frye had and was not used often in trial court proceedings.
• The Daubert opinion was intended to liberalize the admission of evidence and allowed the judge to play the role of the gatekeeper.
• Trial courts should act as “gatekeepers” and exclude expert testimony that is unreliable.
• These rules are in place to help the “trier of fact” understand the evidence and determine its relevance.
• Knowledge is known facts that are “accepted truths.”
Daubert v. Merrell Dow Pharmaceuticals (1993)
Both Frye and Daubert assume a monolithic scientific community
• Who are members of this community? • What constitutes “general acceptance”?• To assist trial court judges the Supreme
Court listed factors to help determine the admissibility of scientific evidence.
• While benefiting the newer quantitative fields of forensic science, these factors, placed greater admissibility pressure on the comparative sciences (fingerprints, hair and fiber).
Daubert Effects
• In some instances expert testimony has been blocked and the “science” of those fields questioned.
• Individuals entering the field of forensic science, and in particular the comparative science, should be aware of the Daubert Hearing and how to prepare for one.
The Daubert Criteria
• In Daubert, the Supreme Court offered some guidelines as to how a judge can gauge scientific evidence:• Whether the scientific technique or theory has
been tested.• Whether the technique has been subject to
peer review and publication.• The technique’s potential rate of error.• Existence and maintenance of standards
controlling the technique’s operation.• Whether the scientific theory or method has
attracted widespread acceptance within a relevant scientific community.
CRIMINALISTICS An Introduction to Forensic Science, 9/EBy Richard Saferstein
PRENTICE HALL ©2007 Pearson Education, Inc. Upper Saddle River, NJ 07458
Kumho Tires Co. v.Carmichael (1999)
• Kumho “plainly invite[s] a reexamination even of ‘generally accepted’ venerable, technical fields.”– United States v. Hines (D. Mass. 1999)
• Handwriting comparison• Fingerprint comparison• Hair comparison• Firearms identification (“ballistics”)
Physical Evidence is Critical
• “You can lead a jury to the truth but you can't make them believe it. Physical evidence cannot be intimidated. It does not forget. It doesn't get excited at the moment something is happening - like people do. It sits there and waits to be detected, preserved, evaluated, and explained. This is what physical evidence is all about. In the course of the trial, defense and prosecuting attorneys may lie, witnesses may lie, the defendant certainly may lie. Even the judge may lie. Only the evidence never lies.”
• - Herbert Leon MacDonell (from Lewis, A. A. and MacDonell, H. L., (1984) The Evidence Never Lies: The Casebook of a Modern Sherlock Holmes, Dell Publishing, New York.)
Value of Physical Evidence Depends on the Quality of the
Forensic Lab• Forensic Science is also fallible and flawed. • In July 1994, U.S.A. Today and the Gannett News
Service published a survey. • O.J Simpson defense claimed the bloody glove
found on his estate was planted. The newspaper thought this was unlikely, so they searched legal and media databases for similar cases. They found 85 instances since 1974 in which prosecutors had knowingly or unknowingly used tainted evidence that had convicted the innocent or freed the guilty.
• In the same period, 48 people sentenced to death were freed after convictions were found to be based on fabricated evidence or because exonerating evidence was withheld.
DNA Exonerations
• Wrongful convictions definitely exist, leading to a rethinking of the death penalty in many cases.
• Barry Scheck and the Innocence Project allege that 1/3 of cases involved “tainted or fraudulent science.”
– Scheck et al., Actual Innocence 246 (2000)
Case Study: Fred Zain• Fred Zain was a police forensic expert in West Virginia
and Texas for nearly 15 years. • Zain was a chemist at the West Virginia State police
crime lab from 1979-1989. He testified as an expert in dozens of rape and murder cases about tests he had never done and results he had never obtained. Despite complaints, nothing was done.
• In 1989, Zain became head of serology at the Bexar County Medical Examiner's office in San Antonio., A Dallas forensic specialist I. C. Stone was asked to review Zain’s work and found rampant fraud and falsification. In one case, Zain had testified about blood evidence when no blood had been found; in other cases he reported performing tests his lab was incapable of doing. Zain was eventually fired.
• At the last count, five men jailed for rape and murder have had their convictions overturned as a result.
Case Study: Fred Zain
• Investigation of W.Va. State Police Crime Lab., Serology Division. – 438 S.E. 501 (W. Va. 1993)– Chief serologist, Fred Zain convicted of
• fabricated reports• perjured testimony
Conflict of Interest• Most forensic scientists are not truly independent
experts. • Most forensic scientists in North America work in
police laboratories; many are themselves law enforcement officers, as are most of their superiors.
• The potential conflict of loyalties and interests is obvious.
• Scientists are expected to retain a critical sense, to follow nothing but reason, to maintain an open mind.
• We expect the results, the science, to bear witness in court unencumbered by any other considerations.
• Complete impartiality may be an ideal but what chance is there of coming anywhere near this ideal if the police or FBI pay your wages?
Maintaining Ethical Standards
• Laboratories are accredited by an independent auditing group, the American Society of Crime Laboratory Directors / Laboratory Accreditation Board
• http://www.ascld-lab.org/• Evidence (typically 50%) is preserved for
independent testing by the defense.• More crime labs are not directly law enforcement,
but lab scientists.• Professional organizations establishing standards• http://www.ascld-lab.org/dual/aslabduallinks.html
Justice Department I.G. Report on FBI Lab (1997)
• Establish report review procedures by unit chiefs;
• Prepare adequate case files to support reports;
• Monitor court testimony in order to preclude examiners from testifying to matters beyond their expertise or in ways that are “unprofessional”; and
• Develop written protocols for scientific procedures.
Regulation of Crime Labs
• New York, Oklahoma, Texas are moving to accreditation of labs
• Certification of examiners– Proficiency testing
• Standardization of procedures– Published protocols
• Increased emphasis on training and credentials.
Participation Question
• Individuals charged with a crime without financial resources currently get a public defender to assist them in their defense at trial.
• Do you think they should also get financial assistance for additional independent forensic testing of evidence? Why or why not?
A Mysterious Disappearance