California Appellate Court Says Defendant Cannot View Algorithm That Contributed Evidence to Guilty Verdict

The use of computer algorithms in statistics-based evidence is more prevalent in criminal cases than many people realize, until they are personally involved in a criminal matter. DNA evidence often involves an expression of the likelihood that a particular defendant’s DNA matches whatever evidence was found in connection with the crime, rather than a definitive statement that the DNA is, in fact, a perfect match. Defense attorneys and other criminal justice advocates complain that the algorithms used in determining these likelihoods are often not shared as part of the criminal trials, and thus part of the proof of a defendant’s guilt is locked in a “black box.” An appellate court in California recently dealt with a discovery request by the defendant to review the algorithm that contributed to his conviction. Continue reading to learn about the the use of secret algorithms in criminal defense cases, and contact a knowledgeable California criminal defense attorney with any questions.

Defendant convicted in part based on DNA evidence asks to see how that evidence was evaluated

In a case entitled People v. Superior Court of San Diego County, the California Court of Appeal considered a discovery request made by a criminal defendant. The first jury that tried the defendant ended up hung. The defendant was then convicted on retrial, but had the conviction overturned on a writ of habeas corpus. On the government’s third go-around, as well as in the first two trials, the government used evidence obtained from a bloody glove found near the crime. The blood on the outside of the glove was indisputably the victim’s, while the inside of the glove had DNA from multiple people and was thus characterized as “complex.”

Police crime labs use software to analyze such complex DNA samples. In this case, they used software the San Diego Police Department purchased from a New Zealand government-owned research institute. The defendant requested discovery of the DNA analysis program, including the user manual, the software program, the source code, and any validation studies and related documents, in order to better make an argument about the efficacy of the DNA analysis. The government refused, citing privacy policies from the company that sold them the software. The defendant also subpoenaed the company, arguing that without the source material he was left outside the prosecution’s “black box” which would show how the evidence proves his guilt and allow him to analyze it for any problems.

Government Keeps Software Algorithm a “Secret” for Criminal Cases

The appellate court, reversing the trial court’s order to produce, refused to compel the company to produce the software. The court held there was nothing to indicate that the DNA analysis software suffered any problems that might have affected the results, and that absent reason to believe the software was not functioning as intended, the defense had no right to see the source information. The court also rejected the defense’s “machine testimony” argument that, because the police lab used the software to make its determination, the program itself was the “expert” that was the source of the evidence, rather than the lab technician, and thus should be available for inspection. The court held that human analysts were still involved at various stages of the analysis, and that “artificial intelligence” and “machine testimony” were not really at stake in this case.

As artificial intelligence develops further and becomes an increasing part of criminal cases, this balance may shift. It is also worth noting that review of source code is common in civil lawsuits, raising the question as to why the concern over disclosure of intellectual property is more important than a defendant’s right to examine the evidence against him fully, given that in a civil context parties often find work-arounds to view such code.

If you are facing criminal charges in southern California, get skilled, seasoned and passionate legal help by contacting the Ventura offices of Paul Tyler for a free consultation at 805-889-9000.