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Friday, December 3, 2010

Exclusive: SFPD Concealed DNA Sample Switch at Crime Lab

Posted By on Fri, Dec 3, 2010 at 3:30 PM

click to enlarge dna_testing.jpg

Records of bungle in 2008 case were destroyed, investigation finds

A forensics analyst's error that resulted in a mix-up of DNA samples, reportedly in a homicide case, has been concealed by officials at the San Francisco Police Department crime lab for close to two years, SF Weekly has learned.

The sample switch, which took place towards the end of 2008, was first alleged in two letters written by an anonymous whistle-blower who worked within the lab at the time. The employee alerted both the San Francisco Public Defender's Office and the American Society of Crime Lab Directors (ASCLD) accreditation board.

When informed of the accusation by ASCLD in August 2009, SFPD crime-lab officials asserted that the complaint was unfounded, stating in a letter to ASCLD that "no instances of corrective action" were on record during the period in question for Tahnee Nelson, the DNA analyst alleged to have made the mistake.

But an interim inspection performed by ASCLD investigators this fall confirmed that "the sample mix-up did occur" and that Nelson's supervisor, then-DNA unit leader Matt Gabriel, was notified but told her to proceed with testing anyway.

The whistle-blower letter to ASCLD. Click to enlarge.
And in what experts call a serious breach of forensics protocol, the mistake was not properly documented or shared with criminal defendants and defense attorneys.

A report on the inspection, which has not been previously disclosed, was provided by the police department in response to inquiries about the alleged sample switch last week from SF Weekly. (You can read the report here.)

The revelation is another serious blow to the credibility of the SFPD crime lab, which was battered earlier this year by reports that narcotics analyst Deborah Madden had stolen drugs for personal use. As a result, the narcotics division of the lab was shut down in March, and drug testing has been outsourced.

While public attention has focused on Madden and problems with drug testing at the crime lab, the flawed handling of evidence in the DNA-testing unit is even more troubling, some say. The DNA lab tests evidence in much more serious cases than those handled by narcotics technicians, many of them rapes and murders.

"Madden was an unfortunate character in this drama... she was really a red herring, compared to this," said defense lawyer Tony Tamburello, who has complained in the past about the quality of DNA analysis at the crime lab. "The reality is that they're not operating within the realm of sound constitutional and scientific principles. There's something drastically amiss with the crime lab."

The response to the whistle-blower letter. Click to enlarge.
It is still unclear exactly how the sample switch took place or which cases may have been affected. Police officials say the mistake was not serious and was promptly corrected, and did not result in any aberration in the final results of the lab's tests.

Yet forensics experts say such confidence is misplaced, and that the crime lab's insistence on denying the switch took place when confronted with a whistleblower's allegations casts a shadow over all work done at the facility.

"For every one of those things that are discovered, there are dozens or hundreds that could have happened. That could result in a false conviction of somebody," said Marc Taylor, president of Technical Associates, Inc., a private crime lab based in Ventura. "If you're going to be switching things, if you're going to be hiding things, if you're going to be saying things didn't happen, you've lost your credibility. That laboratory should be shut down."

Public Defender Calls for Criminal Investigation

ASCLD's findings have angered some San Francisco criminal-defense attorneys, who say the District Attorney's office has not provided the document to them despite its obligation to do so. In May, following the Madden scandal, San Francisco Superior Court Judge Anne-Christine Massullo ordered District Attorney Kamala Harris to develop a policy for turning over exculpatory information about police employees and forensic work to defendants.

"Not only did the lab fail to document the switching of samples. They intentionally covered it up. This is a bombshell," Public Defender Jeff Adachi said of the Sept. 11 ASCLD report, which he received from SF Weekly. "This is something that should have been handed over to our office on Sept. 12."

Adachi said an independent investigation of the practices of the crime lab's DNA unit is necessary, as well as "a criminal investigation as to whether there was an intentional effort to destroy evidence in a criminal case."

David Wise, a private defense attorney who specializes in cases involving DNA evidence, said he has filed motions in ongoing criminal cases asking for ASCLD interim inspection reports, and sought additional information in particular about the whistle-blower complaint, which he discovered among documents released by Harris' office after Massullo's ruling and believes could affect some of his clients' cases. He, too, first learned of the inspection's findings from SF Weekly.

"I just can't believe it. I'm shocked," Wise said. "I'm troubled by the fact that I've asked for exactly this and they've told me it doesn't exist. I think that's enough for me to be disturbed about, when someone's looking at 25 to life."

District Attorney's office spokesman Seth Steward declined a reporter's requests to interview prosecutors who specialize in DNA issues or who work in the office's new trial integrity unit, which was formed to ensure the DA's legal obligation to hand over exculpatory material to defense lawyers is met.

"I'm not going to be able to be helpful on that," he said.

An excerpt from the ASCLD investigation. Click to enlarge.
SFPD spokeswoman Lt. Lyn Tomioka acknowledged that the denials of the lab mishap in police officials' 2009 letter to ASCLD "looked bad" in light of investigators' later findings, but said the lab has made great strides since then in increasing the transparency of its operations.

"We have moved so far forward with the lab that this would be like churning up old history," she said, noting that the SFPD had promptly provided ASCLD's most recent findings to SF Weekly and that the crime lab was re-accredited in October.

Tomioka said a just-completed internal affairs investigation into the whistleblower's complaints found that there was "absolutely no cover-up in this case," and that Nelson's mistake was immediately corrected under Gabriel's supervision. Because of this action, she said, police officials have never tried to determine which defendants' cases were affected by the error.

Jim Mudge, who wrote the letter to ASCLD denying the whistleblower's allegations, is still employed by the SFPD but no longer works as head of the crime lab, Tomioka said. Gabriel left the lab earlier this year and now works at Applied Biosystems in Foster City. Mudge could not be reached for comment, and Gabriel did not respond to a request for comment by publication time. (You can read Mudge's 2009 response to ASCLD here.)

SFPD Capt. Donna Meixner, who in June took over as head of the department's Forensic Services Division, said she believed a record of the mistake had been entered into the lab's computer system, even though it was withheld from the files of any cases affected by the testing.

"I don't think there was any intentional error," Meixner said. "I think it was a human error on the part of the analyst."

Despite the lab's re-certification, ASCLD accreditation board executive director Ralph Keaton said in an interview that the SFPD's initial denial of the sample switch was troubling.

"I guess everyone has to determine in their own mind how serious that is," Keaton said in a telephone interview from the group's North Carolina office. "Obviously, that doesn't make us happy, and obviously, they made some administrative changes. ... If we felt that we had a consistent pattern of misrepresentation, we would find that extremely serious."

 According to the anonymous whistleblower's allegations, Nelson mixed up the samples in a "homicide case that was a rush in the laboratory as the case was going to trial." The whistleblower also wrote, "At the direction of DNA Supervisor Matt Gabriel, the sample switch was covered up by re-labeling the tubes containing the DNA evidence and by manipulating the LIMS system in order to hide the sample switch." (LIMS, which stands for Laboratory Information Management System, is the computer program that manages lab data.)

ASCLD found the switch involved "the last two samples of the batch" in a testing apparatus. Nelson noticed that the last test tube, which should have been clear in color -- what analysts call an "extraction negative" -- was discolored, and that an adjacent tube was clear. According to ASCLD, "The analyst immediately reported this incident to the supervisor. The supervisor authorized the analyst to correct the tube labels and the sample processing proceeded. The DNA typing results were reviewed by the supervisor and the case showed no discrepancies in the DNA typing results, no further corrective actions were taken by the laboratory."

While it is entirely possible that Gabriel and Nelson were able to immediately correct the error, there is no guarantee, according to Jim Norris, a Redwood City-based forensics consultant who headed the SFPD Forensic Services Division for nine years before retiring in 2004. A misplaced tube in a sample batch could potentially indicate that all of the DNA evidence during that round of testing is out of place and mislabeled, Norris said.

"You can say, 'I know how the mistake was made, and I know which two tubes are which.' But are you really sure? The correct thing to do there is go back and start over," he said. Norris said SFPD officials should review and possibly retest DNA evidence from the period when the sample switch occurred to determine what defendants' cases might have been affected.

How many cases affected?

At present, those cases are unknown. While ASCLD found that a handwritten worksheet recording the incident was "transcribed into the laboratory information system," the original notes of the mix-up were destroyed, and no documentation of the incident was found in case records or corrective action logs, where it could be available to defense attorneys as exculpatory material under the U.S. Supreme Court decision Brady v. Maryland.

"Even more troubling than the making of the mistake is the covering of the mistake," said Erin Murphy, a professor at New York University Law School and expert in DNA evidence. "It's bad enough to pretend like it never happened, but when confronted with a direct question, to continue to either lie or obfuscate, I think it's incredibly troubling."

Bicka Barlow, a DNA specialist at the Public Defender's office, received an initial version of the whistleblower complaint in November 2008. That letter stated that the mix-up involved evidence in a homicide case. Barlow said she notified the US Attorney's office in San Francisco of the allegations, and that an FBI agent retrieved a copy of the letter from her. The FBI's San Francisco field office did not return calls as to whether it was conducting an investigation into the incident.

Another letter -- presumably from the same whistleblower, and making identical allegations -- arrived with ASCLD in July 2009. It said the switch took place in "the last quarter of 2008," and happened during Nelson's first DNA case. According to Mudge's August 2009 response to ASCLD's inquiries about the allegation, Nelson handled a total of 33 cases in the last quarter of 2008.

Murphy said those cases, and potentially others, should all be reviewed, and defense attorneys who worked on them should be notified of the sample switch and the SFPD's subsequent denials of it.

"If someone told you, 'I tested you for HIV. There was a sample switch at the lab, but don't worry -- you can trust me,' you would probably want to be tested again," she said.

Other Problems

The whistleblower's letters also alleged that security at the lab has been extremely lax, with doors left propped open and members of the public free to wander inside. "The laboratory is consistently left in an unsecure manner, such that the general public would be able to access the laboratory unattended," he wrote. "On at least two occasions I was working... and was approached from behind by individuals that were able to make their way into the laboratory unescorted."

In its 2009 response to ASCLD, Mudge also denied this allegation. "It is the Laboratory's policy to maintain a secure environment and keep doors shut at all times," he wrote, adding that "Any unescorted individuals who may gain access to the Laboratory work spaces, as the allegation claims, would have been sworn SFPD members seeking lab staff for a case-specific purpose."

This statement was also contradicted by the September 2010 ASCLD report, however.
Accreditation board investigators found that lab Quality Manager Marty Blake "readily admitted" that "the lab had problems with the biometric fingerprint access system working correctly" prior to November 2009, when a new card-access system was installed. "At times before the proximity card system was installed she observed doors to the building and laboratory secure areas were propped open," the report notes.

ASCLD investigators also interviewed criminalist Cherisse Boland in response to a complaint from defense lawyer Tony Tamburello that she had given misleading testimony to a grand jury convened in January 2008. Tamburello had asserted that Boland failed to tell notify him, or the grand jurors, that the majority of the DNA found on a bicycle supposedly used by the suspect in a murder case came from an unknown individual, and not his client.

ASCLD "determined the allegations to be unfounded," but also noted that "an ongoing Management Control Division Investigation in regards to the allegation" is being performed by the SFPD. Meixner said that the investigation is still underway -- meaning that at least two of the DNA lab's small crew of analysts have recently been subject to internal affairs scrutiny.

SF Weekly will be publishing a cover story on problems in the DNA division of the crime lab in its Dec. 15 issue.

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