Com. v. Curnin

• Citation: 565 N.E.2d 440,409 Mass. 218
• Parties: , 59 USLW 2517 COMMONWEALTH v. Robert W. CURNIN.
• Decision Date: 24 January 1991
• Court: United States State Supreme Judicial Court of Massachusetts

Page 440

565 N.E.2d 440

409 Mass. 218, 59 USLW 2517

COMMONWEALTH v. Robert W. CURNIN.

Supreme Judicial Court of Massachusetts,

Worcester.

Argued Oct. 4, 1990.

Decided Jan. 24, 1991.

Andrew Silverman, Boston, Committee for Public Counsel Services (Michael Hussey, Washington, D.C., with him), for defendant.

Katherine E. McMahon, Asst. Dist. Atty. (Thomas E. Landry, Asst. Dist. Atty., with her), for the Com.

Before LIACOS, C.J., and WILKINS, ABRAMS, NOLAN and O'CONNOR, JJ.

WILKINS, Justice.

We consider for the first time the admissibility of the results of tests comparing the DNA of a criminal defendant with DNA found at a crime scene. ¹ The defendant was convicted of rape of a child, burglary, and aggravated rape, and indecent assault and battery. We allowed his application for direct appellate review.

In this case, the DNA comparison, sometimes called DNA fingerprinting, ² tended to prove that semen found on a nightgown of a fourteen year old, handicapped rape victim was that of the defendant. Indeed, the evidence was that only one Caucasian in 59,000,000 has the same distinctive DNA components that were found in the DNA comparison test. Evidence of this nature, based on the scientific principle that every human has unique genetic characteristics and having an aura of infallibility, must have a strong impact on a jury. The erroneous admission of such evidence would undoubtedly be prejudicial in any case where, as here, the identification of the person who committed the crime is in serious dispute. We conclude that the results of DNA testing were improperly admitted in this case. The convictions must be reversed, and the case retried.

The judge considered the admissibility of the results of the DNA testing during a pretrial hearing. An expert witness employed by Cellmark Diagnostics laboratory (Cellmark), the company that conducted the test, carefully described the process by which the DNA in the stain found on the nightgown and DNA taken from a sample of the defendant's blood were put through various steps. Those steps concluded with an autoradiograph that permitted a comparison of genetic material in each sample with respect to four specific sections of human DNA (alleles) that are highly variable among humans. ³

Everyone agrees that the underlying theory and at least the general processes used by Cellmark are accepted in the scientific community. The defendant did not argue below, and does not argue here, that there were defects in the way the testing procedures were conducted in this case. His challenge is in effect a facial attack on the acceptability of the process Cellmark followed. He presented an expert witness who pointed to various problems that exist or may exist in the use of DNA testing for forensic purposes. The impurity of a sample of blood or semen taken from the crime scene may present problems in the testing process. The amount of DNA found at the scene may be insufficient to permit adequate testing, particularly retesting to verify results. The defendant contends also that there is no general acceptance of how such forensic tests should be conducted, of how controls should be included in the testing process, or of the standards of performance to which a testing laboratory should be held.

The judge rejected the defendant's challenges to the admissibility of the evidence. In findings and rulings issued from the bench, she stated that the process was accepted by the scientific community and that the tests in this case were properly conducted. She did not expressly discuss the defendant's challenge to statistical probabilities determined by Cellmark based on its test results. ⁴

The use of DNA testing for forensic purposes is of very recent origin. There are several opinions approving the use of DNA test results to prove the identity of the person who committed a crime. In each of these cases, the defendant made no concerted challenge to the admissibility of the evidence by presenting expert testimony. ⁵ More recently, some courts, instructed by informed challenges backed by expert testimony, have ruled that, at least in the particular case, DNA test results were not admissible. ⁶ Various studies have been conducted or are under way to determine how, if at all, DNA testing should have a role in the proof of identity in a criminal trial. The problem is not in the scientific concepts involved but rather in how those concepts should be implemented.

We need not resolve the propriety of the forensic DNA testing conducted in this case because we conclude that there is no demonstrated general acceptance or inherent rationality of the process by which Cellmark arrived at its conclusion that one Caucasian in 59,000,000 would have the DNA components disclosed by the test that showed an identity between the defendant's DNA and that found on the nightgown. The question of the acceptance of DNA test results in the trial of cases will, no doubt, have to be determined in voir dire hearings in future cases. ⁷ A determination that DNA test results are generally admissible in a criminal trial could aid defendants as well as prosecutors. Evidence that a properly conducted test produced no match would be exculpatory of the person tested.

We have usually applied the Frye test in deciding whether evidence produced by a scientific theory or process is admissible, that is, whether the community of scientists involved generally accepts the theory or process. Frye v. United States, 293 F. 1013 (D.C.Cir.1923). See Commonwealth v. Mendes, 406 Mass. 201, 205, 547 N.E.2d 35 (1989); Commonwealth v. Fatalo, 346 Mass. 266, 269, 191 N.E.2d 479 (1963). The party offering the evidence "has the burden of showing the general acceptance by experts in the field of the reliability" of that evidence. Commonwealth v. Kater, 388 Mass. 519, 527, 447 N.E.2d 1190 (1983). In making the determination whether the test is generally accepted, courts may properly consider not only the evidence in the record but also the reasoning and conclusions of other courts and the writings of experts. Id. In these circumstances, an appellate court makes its own determination without regard to the conclusions of the trial or motion judge. ⁸

The evidence and other material that may appropriately be considered do not warrant the conclusion that Cellmark followed a generally accepted or obviously logical procedure in deciding the likelihood that someone else would have the same DNA characteristics as those that were identified in the comparison test. The prosecutor presented no expert to support Cellmark's conclusion. The prosecution's expert on Cellmark's test procedures acknowledged that she was not qualified to give an opinion on the subject. She, in fact, made certain concessions about the possible unacceptability of the process that Cellmark used. ⁹ The judge made no finding or ruling on the probability issue, even though the defense presented as an expert a population geneticist whose testimony indicated that the data on which Cellmark relied were not adequate to support its conclusion and that certain assumptions underlying Cellmark's approach were not shown to be true.

To determine the frequency with which alleles shown on a test appear in the population, one must have gathered and maintained parallel DNA information in a data base. Obviously, there will be a question whether the data base is appropriate, both generally and specifically as applied to a defendant. The approach taken by Cellmark was to determine, allele by allele, its frequency in the population in its data base and then to multiply each fraction to arrive at the probability of someone else having the same DNA characteristics that were revealed in the DNA comparison test. This process is known as the product rule. ¹⁰ Cellmark compiled its Caucasian data base by testing 200 blood samples collected at a New York City blood bank.

The prosecution's expert granted that there had been "a lot of discussion recently about the population genetics of these highly variable probes," whether the alleles Cellmark used do "behave the same as other much more well characterized loci that have already been studied in human population genetics." For example, genetic marker analysis of blood stains for blood characteristics has been accepted because the nature of the distribution of those characteristics among the population is well-accepted by the scientific community. See Commonwealth v. Gomes, 403 Mass. 258, 273-275, 526 N.E.2d 1270 (1988); Commonwealth v. Beausoleil, 397 Mass. 206, 217-218 n. 15, 490 N.E.2d 788 (1986). There is no showing, however, that scientists agree generally that the distribution of the alleles disclosed in Cellmark's testing is random in the Caucasian population so as to warrant the calculations made by Cellmark.

The defendant's expert, Dr. Laurence Mueller, a population geneticist, testified that Cellmark's data base was not adequate for the purpose of producing an estimate of the frequency of finding a particular genotype in the human population. Cellmark did not have data on missing alleles in certain tests reflected in its data base. There was, in addition, the question whether there is significant substructuring (subgroups) within racial groups that would affect probability determinations using Cellmark's data base, and, if so, whether an acceptable statistical adjustment could be made to account for it. Data from a geographically representative population, rather than from a limited area, should be used. He testified that the forensic scientific community does not agree on what population studies are required (the breadth of the sample of humans and the appropriate level of ethnic information). Moreover, there is no agreement on the consequences of using extremely rare alleles. There are disagreements about using the product rule in the circumstances. ¹¹

There are various criticisms of the soundness of accepting certain assumptions made about...