"I had," said he, "come to an entirely erroneous conclusion which shows, my dear Watson, how dangerous it always is to reason from insufficient data."

Arthur Conan Doyle, The Adventure of the Speckled Band

One way to view science is that it is a search for truth.¹ Forensic science is no exception. As Attorney General Janet Reno emphasized, "The use of forensic science as a tool in the search for truth allows justice to be done not only by apprehending the guilty but also by freeing the innocent."²

This report describes a study that focused on the freeing of the innocent persons initially convicted and imprisoned but later released through postconviction forensic use of DNA technology.

Purpose and Scope of the Study

The principal purpose of the study, initiated in June 1995, was to identify and review cases in which convicted persons were released from prison as a result of posttrial DNA testing of evidence. As of early 1996, researchers had found 28 such cases: DNA test results obtained subsequent to trial proved that, on the basis of DNA evidence, the convicted persons could not have committed the crimes for which they were incarcerated.

The study also involved a survey of 40 laboratories that conduct DNA testing.

This report does not probe the strengths or weaknesses of forensic DNA technology when applied to criminal cases.³ The discussion of DNA instead is limited to its use in exculpating convicted defendants serving prison sentences.

The authors do not claim to be scientific experts in DNA technology. This report cites reference materials that probe technological details more deeply than occurs on these pages.

The balance of this chapter outlines the study's design and provides basic background information on forensic DNA identification testing. Chapters II and III, respectively, present the study's findings and their policy implications. The final chapter consists of brief profiles of the 28 exculpatory cases. A glossary defines DNA related terms, and there are commentaries on DNA testing at the end. (Note: We have not reproduced the appendix which reports DNA test results for some of the exculpated persons profiled in this report. Also, the commentaries, which we have placed at the end, were at the beginning of the original report.)

Study Design

To identify cases that met study criteria-defendant conviction, imprisonment, and subsequent exoneration and release resulting from posttrial exculpatory DNA tests-researchers examined legal and newspaper data bases and interviewed a variety of legal and DNA experts. Once initially identified as likely candidates for the study, cases were verified and assessed through interviews with the involved defense counsel, prosecutors, and forensic laboratory staff; through reviews of court opinions; and, in some instances, through examinations of case files.

For example, initial identification of the Glen Woodall case resulted from an automated search of newspaper data bases, which identified articles about the case in several West Virginia newspapers, the Philadelphia Inquirer, and the Cleveland Plain Dealer. An opinion by the West Virginia Supreme Court of Appeals in the appeal of Woodall's conviction (State v. Woodall, 385 S.E.2d 253, W. Va. 1989) contained the name of Woodall's defense attorney, who was called and interviewed at length and who provided materials related to the criminal case.

Those materials described improper activities by Fred Zain, once a serologist for the West Virginia State Police. A phone conversation with the West Virginia assistant attorney general handling the Zain misconduct cases resulted in the receipt of public case documents containing extensive details on Zain's activities related to the Woodall investigation and prosecution.

A review of transcripts from the criminal and, later, civil cases yielded the name of the laboratory that conducted the DNA testing that exculpated Woodall. A lengthy interview was conducted with the laboratory's forensic scientist who performed the DNA tests on the Woodall evidence. He provided documentation related to his examinations in the case.

Cases related to a special West Virginia Supreme Court of Appeals investigation into government misconduct surrounding Woodall's case (438 S.E.2d 501, W. Va. 1993; 445 S.E.2d 165, W. Va. 1994) also were reviewed.

Researchers collected information for the survey of DNA-testing laboratories through telephone interviews. An experienced crime laboratory director assisted the Institute for Law and Justice in conducting the survey.

This study, conducted in a short time period with limited funding, reflects a modest level of analysis and focuses on a relatively small number of cases. One can state with confidence, however, that as of the study's completion, the 28 cases identified represent most of the situations in the country where convicted felons had been released from prison on the basis of postconviction DNA testing.⁴

Background on Forensic Use of DNA Identification Testing

Perhaps the most significant advance in criminal investigation since the advent of fingerprint identification is the use of DNA technology to help convict criminals or eliminate persons as suspects. DNA analyses on saliva, skin tissue, blood, hair, and semen can now be reliably used to link criminals to crimes. Increasingly accepted during the past 10 years, DNA technology is now widely used by police, prosecutors, defense counsel, and courts in the United States.

An authoritative study on the forensic uses of DNA, conducted by the National Research Council of the National Academy of Sciences, has noted that:

. . . the reliability of DNA evidence will permit it to exonerate some people who would have been wrongfully accused or convicted without it. Therefore, DNA identification is not only a way of securing convictions; it is also a way of excluding suspects who might otherwise be falsely charged with and convicted of serious crimes.5

Forensic use of DNA technology in criminal cases began in 1986 when police asked Dr. Alec J. Jeffreys (who coined the term "DNA fngerprints"⁶) of Leicester University (England) to verify a suspect's confession that he was responsible for two rape-murders in the English Midlands.⁷ Tests proved that the suspect had not committed the crimes. Police then began obtaining blood samples from several thousand male inhabitants in the area to identify a new suspect.⁸ In a 1987 case in England, Robert Melias became the first person convicted of a crime (rape) on the basis of DNA evidence.⁹

In one of the first uses of DNA in a criminal case in the United States, in November 1987, the Circuit Court in Orange County, Florida, convicted Tommy Lee Andrews of rape after DNA tests matched his DNA from a blood sample with that of semen traces found in a rape victim.¹⁰

Two other important early cases involving DNA testing are State v.Woodall¹¹ and Spencer v. Commonwealth.¹² In Woodall, the West Virginia Supreme Court was the first State high court to rule on the admissibility of DNA evidence. The court accepted DNA testing by the defendant, but inconclusive results failed to exculpate Woodall. The court upheld the defendant's conviction for rape, kidnapping, and robbery of two women. Subsequent DNA testing determined that Woodall was innocent, and he was released from prison (see the case profile in chapter IV for more details).

The multiple murder trials in Virginia of Timothy Wilson Spencer were the first cases in the United States where the admission of DNA evidence led to guilty verdicts resulting in a death penalty. The Virginia Supreme Court upheld the murder and rape convictions of Spencer, who had been convicted on the basis of DNA testing that matched his DNA with that of semen found in several victims. In Spencer, the defendant's attack upon the introduction of DNA evidence was limited to the contention that its novelty should lead the court to "hold off until another day any decision . . . ¹³ There was no testimony from expert witnesses that challenged the general acceptance of DNA testing among the scientific community.¹⁴

The first case that seriously challenged a DNA profile's admissibility was People v. Castro;¹⁵ the New York Supreme Court, in a 12-week pretrial hearing, exhaustively examined numerous issues relating to the admissibility of DNA evidence. Jose Castro was accused of murdering his neighbor and her 2-year-old daughter. A bloodstain on Castro's watch was analyzed for a match to the victim. The court held the following:

· DNA identification theory and practice are generally accepted among the scientific community.

· DNA forensic identification techniques are generally accepted by the scientific community.

· Pretrial hearings are required to determine whether the testing laboratory's methodology was substantially in accord with scientific standards and produced reliable results for jury consideration.

The Castro ruling supports the proposition that DNA identification evidence of exclusion is more presumptively admissible than DNA identification evidence of inclusion. In Castro, the court ruled that DNA tests could be used to show that blood on Castro's watch was not his, but tests could not be used to show that the blood was that of his victims.

In Castro, the court also recommended extensive discovery requirements for future proceedings, including copies of all laboratory results and reports; explanation of statistical probability calculations; explanations for any observed defects or laboratory errors, including observed contaminants; and chain of custody of documents. These recommendations soon were expanded upon by the Minnesota Supreme Court, in Schwartz v. State,¹⁶ which noted, ". . . ideally, a defendant should be provided with the actual DNA samples(s) in order to reproduce the results. As a practical matter, this may not be possible because forensic samples are often so small that the entire sample is used in testing. Consequently, access to the data, methodology, and actual results is crucial . . . for an independent expert review."¹⁷

In Schwartz, the Supreme Court of Minnesota refused to admit the DNA evidence analyzed by a private forensic laboratory; the court noted the laboratory did not comply with appropriate standards and controls. In particular, the court was troubled by failure of the laboratory to reveal its underlying population data and testing methods. Such secrecy precluded replication of the test.

In summary, courts have successfully challenged improper application of DNA scientific techniques to particular cases, especially when used to declare "matches" based on frequency estimates. However, DNA testing properly applied is generally accepted as admissible under Frye¹⁸ or Daubert¹⁹ standards.²⁰ As stated in the National Research Council's 1996 report on DNA evidence, "The state of the profiling technology and the methods for estimating frequencies and related statistics have progressed to the point where the admissibility of properly collected and analyzed DNA data should not be in doubt."²¹ At this time, 46 States admit DNA evidence in criminal proceedings. In 43 States, courts have ruled on the technology, and in 3 States, statutes require admission (see exhibit 1).

Endnotes For Chapter I

1. "Science is the search for truth-it is not a game in which one tries to beat his opponent, to do harm to others."Linus Pauling, 1958. Cited in Beck, Emily Morison (ed.), Familiar Quotations, Boston: Little, Brown and Company, 1980.  [Back]

2. Keynote address by Attorney General Janet Reno before the American Academy of Forensic Sciences, Nashville, Tennessee, February 21, 1996.  [Back]

3. For articles debating the forensic use of DNA technology, see Thompson, William, "Evaluating the Admissibility of New Genetic Identification Tests: Lessons from the DNA War," The Journal of Criminal Law & Criminology, 84, 1 (1993):22-104; Harmon, Rockne, "Legal Criticisms of DNA Typing: Where's the Beef?" The Journal of Criminal Law & Criminology, 84, 1 (1993):175-188; and Neufeld, Peter, "Have You No Sense of Decency?" The Journal of Criminal Law & Criminology, 84, 1 (1993):189-202.  [Back]

4. The study's results have been reviewed by many persons, including those involved in a peer review process. To date, no one has identified additional cases that, as of the study's completion in February 1996, are the type examined in this report.  [Back]

5. National Research Council, National Academy of Sciences, DNA Technology in Forensic Science, Washington, D.C.: National Academy Press, 1992:156. (Cited as NRC report.) Another reference source is McKenna, Judith, J. Cecil, and P. Coukos, "Reference Guide on Forensic DNA Evidence," Reference Manual on Scientific Evidence, Federal Judicial Center (1994). This guide has a useful glossary of terms at p. 323.  [Back]

6. Jeffreys, Alec J., Victoria Wilson, and Swee Lay Thein, "Hypervariable 'Minisatellite' Regions in Human Nature," Nature, 314 (1985):67; "Individual-Specific 'Fingerprints' of Human DNA." Nature, 316 (1985):76.  [Back]

7. The first reported use of DNA identification was in a noncriminal setting, to prove a familial relationship. A Ghanaian boy was refused entry into the United Kingdom (U.K.) for lack of proof that he was the son of a woman who had the right of settlement in the U.K. Immigration authorities contended that the boy could be the nephew of the woman, not her son. DNA testing showed a high probability of a mother-son relationship. The U.K. Government accepted the test findings and admitted the boy. See Kelly, K.F, J.J. Rankin, and R.C. Wink, "Methods and Applications of DNA Finger-printing: A Guide for the Non-Scientist," Criminal Law Review (1987):105, 108; Note, "Stemming the DNA Tide; A Case for Quality Control Guidelines," Hamline Law Review, 16 (1992):211, 213-214.  [Back]

8. Gill, Peter, Alec J. Jeffreys, and David J. Werrett, "Forensic Application of DNA Fingerprints," Nature, 318 (1985):577. See also Seton, Craig, "Life for Sex Killer Who Sent Decoy to Take Genetic Test," The Times (London) (January 23, 1988):3. A popular account of this case, The Blooding, was written by crime novelist Joseph Wambaugh, New York, NY: William Morrow & Co., Inc., 1989.  [Back]

9. Bureau of Justice Statistics, "Forensic DNA Analysis: Issues," Washington, D.C.: U.S. Department of Justice, Bureau of Justice Statistics, June 1991, at 4, note 8.  [Back]

10. The admissibility of the DNA evidence was upheld by the intermediate appeals court, which cited the uncontroverted testimony of the State's expert witnesses. State v. Andrews, 533 So.2d 841 (Dist. Ct. App. 1989). See also Office of Technology Assessment, Congress of the United States, Genetic Witness: Forensic Uses of DNA Tests, Washington, DC: July 1990.  [Back]

11. 385 S.E.2d 253 (W. Va. 1989).  [Back]

12. 384 S.E.2d 775 (1989). Additional court appeals by Spencer were rejected by the Virginia Supreme Court at 384 S.E.2d 785 (1989); 385 S.E.2d 850 (1989); and 393 S.E.2d 609 (1990).  [Back]

13. Supra note 12 at 783.  [Back]

14. Id., at 797.  [Back]

15. 545 N.Y.S.2d 985 (Sup. Ct. 1989). Castro's case was never tried. He pleaded guilty to the murders in late 1989.  [Back]

16. Schwartz v. State, 447 N.W.2d 422 (1989).  [Back]

17. Id., at 427. The Minnesota Supreme Court further held that the use of statistical probabilities testimony should be limited because of its potential for prejudicing the jury. Id., at 428. The opinion was later modified in State v. Bloom, 516 N.W.2d 159 (1994).  [Back]

18. Frye v. United States, 293 F. 1013 (D.C. Cir. 1923). The test for the admissibility of novel scientific evidence enunciated in this case has been the most frequently invoked one in American case law. To be admissible, scientific evidence must be "sufficiently established to have gained general acceptance in the particular field in which it belongs."  [Back]

19. Daubert v. Merrell Dow Pharmaceuticals, Inc., 113 S.Ct. 2786 (1993). The Supreme Court used this civil case to articulate new standards for interpreting the admissibility of scientific evidence under the Federal rules of evidence. This standard, while encompassing Frye, allows a court to expand its examination to include other indicia of reliability, including publications, peer review, known error rate, and more. The court also should consider factors that might prejudice or mislead the jury. For the application of Daubert to DNA technology, see Sheck, Barry, "DNA and Daubert," Cardozo Law Review, 15 (1994):1959.  [Back]

20. This brief overview is not a treatise on DNA evidence admissibility in criminal cases. For more authoritative articles, see, Thompson, supra note 3; Kaye, D.H., "The Forensic Debut of the National Research Council's DNA Report: Population Structure, Ceiling Frequencies and the Need for Numbers," Jurimetrics Journal, 34, 4 (1994):369-382; Comments, "Admissibility of DNA Statistical Data: A Proliferation of Misconception," California Western Law Review, 30 (1993):145-178.  [Back]