Title: Caldwell v. State

State: georgia

Issuer: Georgia Supreme Court

Document:

260 Ga. 278 (1990) 393 S.E.2d 436 CALDWELL v. THE STATE. S90A0463. Supreme Court of Georgia. Decided July 3, 1990. Jimmy D. Berry, Bruce S. Harvey, for appellant. Thomas J. Charron, District Attorney, Debra H. Bernes, Nancy I. Jordan, Jack E. Mallard, Assistant District Attorney, Michael J. Bowers, Attorney General, C. A. Benjamin Woolf, for appellee. HUNT, Justice. This case, in which the prosecutor seeks a death penalty, is here on pre-trial review under OCGA §§ 17-10-35.1 and -35.2. 1. The defendant moved the trial court to prohibit the introduction of DNA identification evidence. Between May 8, 1989, and October 31, 1989, the trial court heard evidence, including six experts called by the state and four experts called by the defense. Ultimately, the trial court denied the motion, concluding that the relevant scientific principles and techniques are valid and that the laboratory procedures in this case were performed in a scientifically acceptable manner, "thereby obtaining sufficiently reliable results within a reasonable degree of scientific certainty so as to be admissible in evidence." The admissibility of DNA identification evidence is an issue of *279 first impression in this court.[1] There are at present three private, forprofit laboratories equipped to conduct forensic DNA identification, two of which Lifecodes and Cellmark use essentially the same process. Lifecodes conducted the DNA tests in this case. Considerable testimony was presented in this case about the methodology used by Lifecodes (which in many respects is standard in all DNA research plant, animal or human), about its protocol and standards, and about its population statistics and probability calculations. The defendant's quarrel with DNA identification is not with the science on which it is based, nor with the general scientific acceptability of the techniques used to generate an "autoradiograph." The defendant's concerns essentially are Lifecodes' quality control, the manner in which it declares a "match," and in its probability calculations. (a) It would be helpful at this point to review relevant principles of genetics and cellular biology. We set forth a "brief genetic and biological primer" from People v. Wesley, 533 NYS2d 643 (Co. Ct. 1988): *281 *282 passed on from one generation of cells to the next and from one generation of an organism to the next. It causes a rhinoceros to give birth to a rhinoceros and not to an ant. *285 PRINT IDENTIFICATION TEST." People v. Wesley, supra, 533 NYS2d at 645-60. (b) In many states, the test for admissibility of novel scientific evidence is whether the "scientific principle or discovery" supporting the evidence is "sufficiently established to have gained general acceptance in the particular field in which it belongs." Frye v. United States, 293 F 1013, 1014 (DC Cir. 1923). This is not the test in Georgia. In Harper v. State, 249 Ga. 519, 525 (1) (292 SE2d 389) (1982), we concluded: The evidence in this case clearly demonstrates that the DNA identification techniques used in this case are based on sound scientific theory and that, if proper procedures are followed, analysis of clean, undegraded samples of sufficiently high molecular weight DNA can produce reliable results. There is no real dispute about this. The dispute centers on the techniques and procedures followed (or not followed) by Lifecodes in this case. Initially, then, we need to decide whether such concerns go merely to weight or whether they implicate admissibility also. We recognize that, while the DNA identification procedures and technology used in this case have been widely used in laboratories for years in experimental and diagnostic settings, the transfer of this technology to a forensic setting is comparatively recent. As noted previously, there are three private laboratories in this country doing forensic DNA analysis. One of them uses procedures entirely different from those explained above (and the record in this case does not explain what those procedures are). The other two use essentially the same technology, but their protocols are different, and they use different restriction enzymes and different probes. The FBI has recently set up its own forensic DNA lab, using still different restriction enzymes and probes. One consequence of this is that the database generated by each system for use in probability analysis is unusable by the other laboratories. In other respects, there may be disagreements at present about, for example, what is a match. Because of "band shift," two lanes of identical samples may not run exactly the same, raising questions such as: How much variation can exist before a match is not a match? What tests, if any, should be run to determine whether a difference in the pattern on two lanes of an autoradiograph is due to band shift? In light of the novelty of the use of DNA analysis in forensics, the complexity of the tests, and the present lack of national standards governing such tests, we conclude the trial court was correct when it determined not just whether the general scientific principles and *287 techniques involved are valid and capable of producing reliable results, but also whether Lifecodes substantially performed the scientific procedures in an acceptable manner. Compare Minnesota v. Schwartz, 447 NW2d 422, 428 (Minn. 1989); People v. Castro, 545 NYS2d 985 (Supp. 1989). We believe this approach is consistent with Harper v. State, supra, 249 Ga. at 524-526. (c) This does not mean that the trial court must exclude novel scientific evidence unless convinced there is no possibility of error. No procedures are infallible. If, for example, a sample was accidentally mislabelled, and the laboratory compared two samples from the same source believing it was comparing a sample of evidence with a sample from the defendant, the result would be a false match. Or, if the laboratory mistakenly or carelessly added sample material from the defendant to the evidentiary sample, and the evidentiary sample was very degraded leaving no bands on the autoradiograph, the bands from the defendant's sample in evidence lane would match the bands in the lane assigned the defendant's sample, and, again, a false match would occur. Obviously, a laboratory needs to take precautions at all stages of its testing procedures. The defendant's experts testified about various ways that errors conceivably could occur, including mislabelling and cross-mixing of samples, bacterial contamination, less than perfect chemical preparations, and so forth. We agree with the trial court's assessment that Lifecodes' protocol is adequate to meet these concerns. More significant were criticisms about: (1) the manner in which a match was declared; (2) Lifecodes' failure (initially) to test for band shift; and (3) the probability estimates. (d) Samples from the same person will not run at exactly the same speed every time. The buffer, the agarose gel and the salt solution are all manufactured and can vary minutely between one batch and the next. Moreover, the gel may not be absolutely consistent across its length, and the lanes into which the samples are poured can have minor variations and imperfections which can affect speed from one lane to the next. The result is called band shift: The banding patterns of two different samples containing the same DNA may not line up exactly they will be close, but not exact. A match can nevertheless be called if the bands are in essentially the same place within a permissible degree of error. The matches in this case were initially declared by visual means. Lifecodes contended that a visual observation was adequate to declare a match, and that it was not necessary to run further tests to document that any difference was due to band shift rather than different DNA. Some band non-alignment was noted and ascribed to band shift, but no tests were run to establish band shift. However, possibly in response to the decision in People v. Castro, supra, 545 *288 NYS2d 985 (which involved a Lifecodes DNA analysis), as well as criticisms by defense experts in the initial hearings in this case, Lifecodes decided to run a test in this case to determine band shift. There are two ways to test for band shift. First, a mixed-lane sample can be run. Here, a part of the known sample and the evidence sample are run in the same lane. If only two bands appear,[4] the DNA is the same. Of course, a mixed lane cannot be run after the evidence sample is used up. Lifecodes took the alternate route, and rehybridized the membrane with a non-polymorphic (or monomorphic) probe. A non-polymorphic probe will attach to DNA which everyone has, and so samples from different people should generate identical banding patterns. Since the non-polymorphic probe is run on the same nylon membrane which generated the previous autoradiographs,[5] the lanes in the autoradiograph derived from running the non-polymorphic probe can be compared to previous ones, and the differences from one lane to the next can be compared. Dr. McElfresh from Lifecodes testified that the results of the test confirmed the presence of band shift and confirmed his previous testimony interpreting the autoradiographs. Agreeing with him on this count were Dr. Wyatt W. Anderson, Alumni Foundation Distinguished Professor of Genetics, member of the National Academy of Sciences and former President of the American Genetic Association; Dr. Sidney R. Kushner, head of the Department of Genetics at the University of Georgia; and Dr. Martin L. Tracey, Professor of Biology at Florida International University in Miami, Florida. These witnesses agreed that visual observation of the autoradiograph, when coupled with the results of the band-shift test, can justify declaring a match, and did so in this case. It may be concluded that declaring a match by visual observation is scientifically acceptable at least where, as here, the visual observation is confirmed by a scientifically acceptable test for determining band shift. (e) Once a "match" is declared, its significance is determined by statistical analysis, applying theories of population genetics: People v. Castro, supra, 545 NYS2d at 992. The defendant complains of Lifecodes' use of a "double integral Gaussian weighted average" in its calculations. We need not consider this complaint, as Lifecodes subsequently revised its calculations using a "straight binning method," which the defendant does not complain about. He does complain that Lifecodes' statistical calculations assume the relevant population is in Hardy-Weinberg equilibrium[6] and that for each of the relevant alleles, the population is in linkage equilibrium. See People v. Castro, supra, 545 NYS2d at 992-93. There was testimony in this case (by state's witnesses) that these assumptions are not unreasonable. However, none of the state's witnesses had studied Lifecodes' database to determine whether the relevant population is in Hardy-Weinberg equilibrium. Only a defense witness attempted to make that determination. Dr. Jung Choi, molecular geneticist, member of the faculty at the Georgia Institute of Technology and consultant to the U. S. Army Criminal Investigation Laboratory, testified that he had analyzed Lifecodes' databases and concluded that the populations were not in Hardy-Weinberg equilibrium. This testimony essentially is undisputed, and seriously calls into question Lifecodes' claimed power of identity one in twenty-four million for the defendant's DNA identification. However, as has been noted, "[c]onservative or reduced calculations may ... correct ... Hardy-Weinberg deviation problems." People v. Castro, supra, 545 NYS2d at 993. Dr. Anderson testified (for the state) that Lifecodes' calculations *290 were based on a number of assumptions, which Dr. Anderson characterized as "not unreasonable." However, Dr. Anderson testified, a more conservative approach is simply to use the database itself, and not "any population theory" to generate frequencies of "individuals" from frequencies of "patterns." His "conservative" power of identity was one in approximately 250,000. Although in a future case the state may establish scientifically that the populations represented in Lifecodes' (or some other laboratory's) databases are in Hardy-Weinberg equilibrium, we conclude the state has not done so in this case. Thus, the state should not be permitted to use Lifecodes' enormous claimed power of identity based on its "assumption" that the relevant population is in Hardy-Weinberg equilibrium. The state may, however, use the more conservative figures Dr. Anderson calculated. Compare People v. Wesley, supra, 533 NYS2d at 659 (reducing "overall claimed mean power of identity ... to eliminate any possible Hardy-Weinberg disequilibrium"). (f) It should be noted that the defense was well-assisted by experts on the issue of admissibility of DNA identification evidence, and that Lifecodes' testing procedures, data and results were disclosed to the defense. Compare Minnesota v. Schwartz, supra, 447 NW2d at 429 (II) (DNA test results not admissible where Cellmark laboratory failed to make its testing data and results available to the defense). (g) In all respects save that of the population statistics, the trial court's order is affirmed. 2. Shortly after 3:00 p. m. on August 16, 1988, Kay Caldwell (the defendant's wife) called the police to report that her children had been stabbed. The police arrived minutes later and were invited into the apartment by Mrs. Caldwell. They found 12-year-old Sara Caldwell lying on the bed, stabbed to death, and 10-year-old Ben Caldwell lying in the bathroom floor, seriously injured, but still alive. Police searched the apartment, looking for evidence until 10:00 p. m. that evening, and continued searching the next day. The defendant and his wife did not remain in the apartment after the murder, and stayed with relatives. The defendant disappeared on August 20, and an arrest warrant was issued August 23, 1988. The police did not obtain a written consent to search until August 21, 1988. Eight months later, Mrs. Caldwell signed a consent to search purportedly ratifying all police searches of her apartment on or after August 16, 1988. The defendant concedes Kay Caldwell "initially ... consented to and in fact requested that the police enter her home." However, he objects to the "scope and intensity" of the search. Relying on Mincey v. Arizona, 437 U.S. 385 (98 SC 2408, 57 LE2d 290) (1978), he argues that there is no crime-scene exception to the warrant requirement, *291 and that while exigent circumstances justified the initial entry by police into the Caldwell apartment and a limited search for a killer or victims on the premises, the search here went well beyond that justified by the exigencies of the situation. Our answer is that the searches here were not based on "exigent-circumstances"; they were based on Kay Caldwell's consent. Kay Caldwell (the sole lessee on the apartment) called the police because her children had been stabbed, and she wanted the police to investigate the crime. She invited them into her home, and then left, entrusting it to the police. Her later written consents to search confirm her intent. The police obtained the defendant's clothes and a key by consent. Later, his truck was searched after having been abandoned by the defendant in some woods one-half mile from the expressway in Gilmer County. See Williams v. State, 171 Ga. App. 546 (2) (320 SE2d 389) (1984). Consensual searches do not violate the Fourth Amendment. The trial court properly denied the defendant's motion to suppress. 3. The court did not err by denying the defendant's motion to require the state to produce "any and all" audio and video recordings of interviews with state's witnesses. Boatright v. State, 192 Ga. App. 112 (2) (385 SE2d 298) (1989). 4. Contrary to the defendant's contention, we have held that the state is entitled to obtain a copy of a written scientific report by a defendant's expert, just as the defendant is entitled to obtain a copy of a written scientific report by a state's expert. Sabel v. State, 248 Ga. 10, 18 (6) (282 SE2d 61) (1981); OCGA § 17-7-211. Moreover, the defendant's expert may be called as a witness by the state. Ibid.; Weakley v. State, 259 Ga. 205 (2) (378 SE2d 688) (1989). 5. Except as noted in Division (1) (e) and (g), supra, the trial court's orders at issue on this appeal are affirmed. Judgment affirmed in part, reversed in part. All the Justices concur. [1] DNA (deoxyribonucleic acid) is an organic substance found in the chromosomes in the nucleus of a cell. It provides the genetic code which determines a person's characteristics. Research laboratories have been conducting DNA analyses for years. The forensic use of DNA analysis, however, is of quite recent origin. [2] While some sources describe the initial 6 steps as "Southern Blotting," any difference in nomenclature does not affect the outcome of this decision. [3] Compare People v. Castro, 545 NYS2d 985 (Supp. 1989), which also describes DNA identification evidence. That opinion includes a footnote which serves as a bibliography for further reading in this area. People v. Castro, supra at 990, n. 3. [4] This assumes (1) that a single-locus probe is being used, and (2) that there is no homozygosis at the locus being probed. [5] Each time a different probe is run, the old probe is chemically washed off, the new probe is hybridized to the samples on the membrane, and a new autoradiograph is made. Theoretically, a membrane could be rehybridized indefinitely. There was testimony, however, that in practice each wash takes off some of the sample as well as the probe, so that eventually the remaining sample will be too small to generate a readable autoradiograph. [6] In 1908, Dr. Hardy and Dr. Weinberg formulated a binomial equation used to calculate the frequency of an allele in a population from sample population data. This equation is valid only if there is random mating in the population, if there is no inbreeding, if there is no mutation, and if the population is effectively infinite.