San Diego Cases involving DNA prior to April 2011 need to be reviewed… immediately. And the San Diego DA’s office has known this for a long time.

In April 2011, the San Diego Police Department (SDPD) crime lab fundamentally changed the way it interprets DNA evidence involving mixture samples. Mixture samples are DNA evidence collected that contain biological material from two or more people.

Prior to April 2011, the SDPD was very liberal about making match inclusions in mixture samples.  That changed in April 2011.  This all came about because the Scientific working Group on DNA Analysis Methods (SWGDM) published updated interpretation guidelines for DNA mixture samples in 2010.  SWGDAM is a national association of forensic DNA scientists who recommend quality assurance standards for forensic laboratories all over the country, including the FBI.  The 2010 SWGDAM guidelines proposed a much more conservative approach to interpreting mixture samples.  The change was, in part, a response to criticism from world renowned DNA scientist Bruce Budowle and others.

After SWGDAM published its 2010 guidelines, many crime labs across the country followed suit and implemented new interpretation protocols in line with the 2010 SWGDAM guidelines.  Because of these significant changes in interpretation protocols, some jurisdictions began reviewing older cases to determine whether there were any convictions that were based on the old, outdated protocols.  Such reviews were initiated, for example, by a District Attorney’s Office in Texas.

The San Diego Police Department crime lab also updated their guidelines and no longer uses the outdated protocols. Hopefully, your jurisdiction did the same.  However, any pre-2011 convictions based on DNA inclusions of mixed DNA samples may, and probably did, use the outdated interpretation protocols. Many of these convictions, if re-evaluated under the new SDPD crime lab protocols (and SWGDAM guidelines), would be inconclusive.  Many others may still be inclusions but with a less compelling population frequency associated with the inclusion.

In other words, DNA opinion evidence may have changed in many cases that substantially benefits the defense, either because the person is no longer considered an inclusion, or they are included at a far lesser probability.

I am currently prosecuting a state Writ of Habeas Corpus on this very issue.  My client was considered a minor contributor to a swab of the inside palm area of a pair of gloves according to the outdated DNA protocols.  When re-evaluated under the new guidelines, in was inconclusive whether he was a contributor.  All substantive filings on this state writ can be found here.

The San Diego District Attorney’s Office knew about this DNA issue in 2011.  But they didn’t tell anyone.

As part of my investigation into the matter, I discovered a memo from the SDPD Crime Lab to the San Diego District Attorney’s Office dated May 4, 2011 detailing the changes in the interpretation guidelines. The memo specifically informs the DA’s office that the new guidelines will result in more samples that cannot be interpreted.  It states “It is likely the new SDPD guidelines will result in more samples that cannot be interpreted due to their complexity and/or low level.”

For the defense community there are some very obvious and important implications here. Convictions prior to April 2011 that were based on a defendant’s DNA being included in a mixture sample, must be reviewed to see if the new guidelines result in a favorable interpretation for the defense.

Under Penal Code 1473(e)(1), a fundamental change in expert opinion is considered a “repudiation” and is grounds for writ of habeas corpus if such opinion is relevant and material on the issue of guilt. This means that if the person convicted was an inclusion, but under the more recent guidelines it is inconclusive, he may have specific statutory relief under Penal Code 1473(e)(1) based on repudiation of the expert’s opinion at trial.  See In re Richards (2016) 63 Cal.4th 291.

Even further, the fact that the San Diego County DA had this information in 2011 and did not alert the defense community or start its own review of affected cases, raises some serious issues of public concern. The inaction of the DA’s office may be a wide scale “Brady” (Brady v. Maryland (1963) 373 U.S. 83.) violation and it must be investigated.

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