People v. Chubb

Facts

In December 1977, Police found a17-year-old Shelley H. in her Long Beach apartment. She was lying on the end of the bed with her feet touching the ground and with an electrical wire tied around her neck. During an autopsy, swabs were taken from her vagina and smeared onto slides. In June 2011, as part of a cold case investigation, Sorenson Forensics (Sorenson) conducted a DNA test on those vaginal swabs and  generated a DNA report that indicated three contributors to the DNA: a major sperm DNA profile attributable to an unidentified male, a minor sperm DNA profile, and a partial DNA profile attributable to the victim. Sorenson excluded the victim's husband, Nolan Hankins, as the source of the major sperm DNA profile. Detectives arrested Chubbs (D) in August 2012. D confirmed that he lived in Long Beach in the 1970s. In September 2012, Sorenson compared the DNA profile of D, an African-American, to the major sperm DNA profile and found a match. The frequency of the profile occurrence in the general population was determined to be one in approximately 10,000 for African Americans. D was held to answer for one count of murder. P sent the vaginal slide to Cybergenetics' lab in Pittsburgh, Pennsylvania for further testing. Cybergenetics prepared a supplemental report, explaining that it had used its TrueAllele software to 'infer possible DNA contributor genotypes from the samples,' then compared the evidence genotypes to the reference genotypes (which included D's and Hankins' genotypes) to compute likelihood ratio DNA match statistics. 'TrueAllele assumed that the evidence sample data . . . contained two or three contributors, and objectively inferred evidence genotypes solely from these data.' The report stated that the DNA match between the vaginal sperm sample and D is '1.62 quintillion times more probable than a coincidental match to an unrelated Black person.' The DNA match with Hankins was '2.82 million times more probable than a coincidental match to an unrelated Black person.' D made numerous discovery requests for the source code for TrueAllele. In January 2014, D filed a motion to compel discovery that included the request for Cybergenetics' source codes. According to D, the TrueAllele program was 'brand new' and had not been the subject of a Kelly hearing, and without the source codes, there would be no way to cross-examine anyone about the efficacy and accuracy of the program. On January 15, 2014, P filed an opposition to the motion to compel discovery, arguing that they requested the source code from Cybergenetics, but Cybergenetics did not turn it over because it is a trade secret. P argued that disclosure of the source code would be 'financially devastating' to Cybergenetics. D argued that the source codes were essential to his defense because the DNA evidence from the vaginal slide was the only evidence against him. D argues that the discrepancy between the random match probability calculated by Sorenson (1 in approximately 10,000) and the likelihood ratio calculated by Cybergenetics (1.62 quintillion times more probable than a coincidental match) to argue that the source codes were necessary to cross-examine anyone about the accuracy of TrueAllele. Allan Jamieson, an expert in DNA analysis who had experience with TrueAllele, could not properly defend against the TrueAllele results without the source codes; 'access to this code is the only satisfactory and professionally recommended way to fully consider the validity of the TrueAllele analysis' in this case. The trial court issued a certificate for an out-of-state subpoena, to produce the source codes. On June 16, 2014, a Pennsylvania court issued an order directing compliance with the subpoena duces tecum. P moved to quash the subpoena duces tecum. P argued that the materials are a trade secret, that D has not established the source codes are material or necessary, and that the discovery is not permitted by section 1054, subdivision (e). The court indicated that it would follow the procedure set forth in Evidence Code sections 1061 and 1062, by issuing a protective order and, if needed, excluding the public from the proceedings. The court deemed the TrueAllele source code a trade secret for purposes of the trial. The court indicated that the source code would be revealed to a certain extent at trial. P refused to turn over the source code. D requested the exclusion of the TrueAllele results at trial. The court granted the request based on D's rights under the confrontation clause. P petitioned for a writ of mandate

Issues

Rule of Law

Holding and Decision

Legal Analysis

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