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the dna wars are over [Excerpted from Convicted by Juries, Exonerated by Science (National Institute of Justice, 1996)]

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 fingerprints" 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. Woodall 11 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, kidnaping, 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'swatch was analyzed for a match to the victim. The court held the following:

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

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

o 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 sample(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 refusedto 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 techniquesto particular cases, especially when used to declare "matches" based on frequency estimates. However, DNA testing properly applied is generally accepted as admissible under Frye 18 or Daubert 19 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).

Exhibit 1. DNA Evidence Admission in Criminal Trials by State

StateDNA Admitted
Colorado Yes
Idaho Yes
Kansas Yes
Maryland Yes*
Nevada Statute
New HampshireYes
New JerseyYes*
New Mexico Yes
New York Yes
North CarolinaYes
North DakotaNo
Pennsylvania Yes
Rhode IslandNo
South CarolinaYes
South DakotaYes
West VirginiaYes
Wisconsin Yes
Wyoming Yes

* Decision by Intermediate Court of Appeals


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.

2. Keynote address by Attorney General Janet Renobefore the American Academy of Forensic Sciences,Nashville, Tennessee, February 21, 1996.

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'sthe 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.

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.

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, FederalJudicial Center (1994). This guide has a usefulglossary of terms at p. 323.

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.

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 Fingerprinting: 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.

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 Decoyto 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, N.Y.: William Morrow & Co., Inc., 1989.

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

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 UnitedStates, Genetic Witness: Forensic Uses of DNATests, Washington, D.C.: July 1990.

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

. 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).

13. Supra note 12 at 783.

14. Id., at 797.

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.

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

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).

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."

19. Daubert v. Merrell Dow Pharmaceuticals, Inc.,113 S.Ct. 2786 (1993). The Supreme Court used this civil case to articulate new standards forinterpreting 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.

20. This brief overview is not a treatise on DNA evidence admissibility in criminal cases. For more authoritative articles, see, Thompson, supra note3; Kaye, D.H., "The Forensic Debut of the NationalResearch 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," CaliforniaWestern Law Review, 30 (1993):145-178.

21. National Research Council, National Academy of Sciences, The Evaluation of Forensic DNA Evidence(prepublication copy), Washington, D.C.: National Academy Press, 1996:2.14.

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