State v. Pickett

Facts

Two police officers traveling in an unmarked vehicle observed two men, later identified as D and co-defendant Jonathan Ferrara, approach a group gathered near the intersection with Van Nostrand Avenue, simultaneously raise their handguns, and fire into the crowd. One victim sustained a bullet wound to the head and was pronounced dead at the scene. A second victim, a ten-year-old girl, suffered a non-fatal wound to the abdomen when a bullet entered a vehicle in which she was sitting. The officers pursued D and Ferrara as they fled down a side street with their guns still in hand. The police arrested them within a few blocks of the incident. Police found a Colt .45 caliber semi-automatic handgun while retracing Ferrara's path, and recovered a .38 caliber Smith and Wesson revolver and ski mask while retracing D's path. A forensic scientist detected the presence of amylase, a constituent of saliva, on the ski mask, and investigators swabbed the trigger guard, grip, and front sight of both weapons and the magazine of the Colt .45 for DNA evidence. Analysts determined that the samples from the guns and from the mask failed to meet the criteria for traditional DNA analysis, but that two specimens from the mask each reflected a mixture of DNA profiles, one with two contributors and the other with three. A comparison with buccal swab samples taken from D and Ferrara showed that D was the major source contributor for the DNA profiles from both the ski mask specimens conducive to traditional analysis. The remaining samples failed to satisfy the criteria for traditional DNA analysis. P forwarded the testing data to Cybergenetics Corp. Laboratory (Cybergenetics) for analysis using its proprietary TrueAllele computer software program. Ferrara was not identified as a contributor to any of the samples under the statistical analysis. D was identified as a source of the DNA on the Smith and Wesson and the ski mask. DNA analysis is more difficult with complex mixtures, particularly where the genetic material involved is small. Analysis of small samples often entails allele 'drop-in'-the detection of an allele from a contaminant DNA fragment that was not part of the original sample-or 'drop-out'-the failure to detect an allele from DNA belonging to the sample, usually due to insufficiency of the quantity for analysis. Analysis of these types of samples is inherently more probabilistic and leaves more room for interpretation than for the single-source or simple-mixture samples that have been traditionally subject to traditional DNA testing. The TrueAllele Casework system employs probabilistic genotyping, the 'use of biological modeling, statistical theory, computer algorithms, and probability distributions,' to 'assist,' rather than 'replace,' 'the DNA analyst in the interpretation of forensic DNA typing results.' It uses mathematical models and simulations, subject to parameters programmed into the software to account for drop-in or drop-out effects and other issues, to calculate a likelihood ratio-a statistic measuring the probability that a given individual was a contributor to the sample against the probability that another, unrelated individual was the contributor. The judge qualified Dr. Perlin, a co-founder of Cybergeneticsas, an expert in 'the fields of DNA Evidence, Interpretation, and Likelihood Ratio.' D moved for TrueAllele's software source code and related documentation. D challenged the reliability of the probabilistic genotyping program, refusing to blindly accept validation studies involving Dr. Perlin, none of which were, as PCAST called for, independent studies to investigate whether the program's software correctly implemented the underlying probabilistic genotyping methods. The parties submitted written declarations by experts detailing, among other things, the uncertainty involved in DNA mixture interpretation, the need for verification and validation (V & V) of software engineering, the existence of software engineering failures, and materials relevant to testing probabilistic genotyping software. Mr. Adams, D's expert, has important and extensive experience performing probabilistic genotyping analyses, including undertaking review of source codes. He reviewed 'software development materials, including source code, for [the] probabilistic genotyping systems STRmix and FST used in criminal cases in New York, Illinois, United States, and Australian courts.' Adams testified that systems such as TrueAllele involve a hierarchy of models with dozens or hundreds of parameters, each affecting the overall system's behavior. Adams pointed out that forensic DNA analysis 'lacks formal standards specific to the development and validation of probabilistic genotyping software.' He also testified to a truism that software quality unquestionably depends in part on the 'quantity and severity of defects present in the program.' He spelled out that defects cause incorrect and misleading results. One goal of the V & V processes is to assure 'appropriate . . . methods have been used throughout the software development process and have produced an acceptable product.' V & V involves reviewing software development materials for 'correctness, completeness, consistency, and accuracy.' Dr. Perlin testified that although the software program itself is patented, its source code is not disclosed in patent documents; instead, Cybergenetics 'considers the . . . source code to be a trade secret.' Dr. Perlin claimed that access to the source code would be 'immaterial to a criminal case,' 'unreasonable,' and not 'in the interests of justice.' TrueAllele's software program consists of approximately 170,000 lines of source code written in MATLAB, a mathematical programming language designed specifically for visualizing and programming numerical algorithms. Dr. Perlin volunteered that it could take hours to decipher only a few dozen lines of the 'dense mathematical text' comprising the code, and estimated that it would take a person, reading at a rate of ten lines per hour, about eight and a half years to review the code in its entirety. Secrecy gives Cybergenetics a commercial 'advantage over its competitors' because they do not know-nor does anyone else-the proprietary code. Once divulged, proprietary trade secrets, Dr. Perlin explained, are 'valuable to competitors' and can be 'sold for profit.' Dr. Perlin neglected to acknowledge the lessons learned from STRmix and FST, which were revealed once other courts forced them to make accessible their source codes for independent review under protective orders. Cybergenetics offered D an opportunity for 'inspection' of the source code under a severely restrictive non-disclosure agreement (NDA), which limited inspection to an expert witness retained by defendant at a time and place determined by the company, under supervision by a company representative, and video surveillance and recording at all times. Adams emphasized that the restrictions would undermine an effective review of the source code for purposes of assessing TrueAllele's reliability. The restrictions do not permit adequate 'documentation of the inspection process and collection of demonstrative materials,' and the inability to compile or execute the source code would be detrimental to any 'rigorous . . . inspection.' The ban on email communication would restrict his consultation with defense experts in other relevant fields, such as biology, statistics, or software development, which would be necessary for understanding and evaluating the source code and related proprietary information. Adams did not believe any expert would agree to the automatic assumption of all liability for a breach. D proposed a protective order provided that the materials would remain confidential and used solely for purposes of preparation of D's defense in this matter, that no recipient could 'reveal, use, or disclose any part' of it, except in compliance with the restrictions in the order, and that no third-party could be granted access without first agreeing to be bound by the same terms. All materials, moreover, would be filed under seal, and all counsel would be bound to take all 'reasonable and appropriate measures to prevent unauthorized disclosure,' with any violation subject to civil and criminal sanction. Eventually, the judge entered an order denying D's motion. It allowed for inspection but nothing close to being able to determine if the software is any good. D maintains the parameters the State has thus far offered are unreasonably burdensome and restrictive. D was granted leave to appeal. In party, D contends P never requested a limited remand to expand the Frye record with additional testimony by Dr. Perlin or anyone else. Most important, D re-emphasizes that errors in the source code of probabilistic genotyping software have been found. There is no reason to assume that TrueAllele, whose source code has never been subject to outside inspection, is immune from these errors. D also contends that simply because the materials are a trade secret does not shield the materials from disclosure and that P has failed to demonstrate that its reliability can be assessed without the type of access that D seeks. 

Issues

Rule of Law

Holding and Decision

Legal Analysis

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