3 DNA Samples Possibly Tainted, Witness Says

Molecular biologist John Gerdes testified Thursday that the Los Angeles Police Department’s protocol for processing evidence in the O.J. Simpson case carried an “unacceptable risk” of error--but he could cite only three DNA tests that showed signs of contamination.

Gerdes testified that he spotted possible contamination in two stains recovered from Simpson’s Ford Bronco, and in one of five blood drops leading away from the bodies of Nicole Brown Simpson and Ronald Lyle Goldman.

Previous witnesses have testified that all three stains were consistent with O.J. Simpson’s blood, and that the Bronco blood also contained faint traces of genetic markers that could have come from Goldman. Gerdes, however, declared DNA test results on all three samples unreliable. And he suggested that results on other blood evidence could not be trusted either.

However, on cross-examination, Gerdes conceded that with the exception of those three tests he could find “no direct evidence” of contamination, only of risky collection techniques. As attorney Thomas Lambert walked him through five easels full of DNA test results, Gerdes acknowledged again and again that he found no trace of contamination in the vast majority of blood evidence--including stains found at the crime scene, in Simpson’s foyer, on bloody gloves and on socks collected from Simpson’s bedroom.

Lambert also used his cross-examination to portray Gerdes, who runs a private immunology lab in Denver, as a hired hack paid to testify about matters outside his areas of expertise. In response to Lambert’s questions, Gerdes acknowledged that he has no experience and no training in the use of DNA tests in criminal cases.

Still, Gerdes insisted that he had valid concerns about the DNA evidence in the Simpson case. “I feel that the sample collection, manipulation and protocols [in the LAPD crime lab] are such that there’s an unacceptable risk of cross-contamination,” he said.

His testimony set the stage for the defense to contend that the DNA tests incriminating Simpson are meaningless because the people who collected and processed the blood were sloppy. In Simpson’s criminal trial, the defense successfully argued that point, dismissing the DNA results with the disdainful mantra “garbage in, garbage out.”

To bolster that argument, defense attorney Robert Blasier played the video LAPD criminalists produced during the criminal trial to show off their evidence collection techniques.

At Blasier’s prompting, Gerdes narrated the video, describing numerous bloopers that he said could cause contamination.

For instance, Gerdes pointed out that criminalist Andrea Mazzola rested her hand on dirty pavement, then picked up the tweezers used in the collection process. He also condemned Mazzola for failing to change gloves between each sample and for rinsing the tweezers with water instead of using new, sterile instruments for each blood drop.

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Gerdes used folksy metaphors to explain to jurors just how easily DNA samples could be contaminated. He told jurors that a criminalist could get a speck of DNA on his gloves and transfer it to his pen while taking notes. Gerdes said the criminalist could pick up the DNA off the pen hours later, without even realizing it, and then accidentally plop it into another blood sample.

Gerdes added that he found evidence of such contamination in the vials of blood drawn from the murder victims during their autopsies. Both vials, he said, contained genetic markers that could have come from O.J. Simpson, suggesting that Simpson’s DNA may have been transferred around in the LAPD crime lab. The plaintiffs’ scientific witnesses have disputed that conclusion.

In addition to attacking Mazzola, Gerdes criticized the work of LAPD criminalist Collin Yamauchi. Gerdes contended that Yamauchi violated a key rule by handling evidence samples at the same time as “reference samples” of blood from the victims and Simpson. And he took Yamauchi to task for processing 23 samples in a single day, saying that technicians who take proper precautions usually process just four or five samples a day.

Gerdes also suggested that something was odd about the blood collected from the socks in Simpson’s bedroom and from the rear gate of Nicole Simpson’s condominium. Those blood samples had a much higher concentration of DNA than other evidence. The defense contends that’s because they were planted directly out of the DNA-rich reference vials.

After Gerdes’ testimony, Judge Hiroshi Fujisaki held a painstaking hearing to review the plaintiffs’ many objections to videotaped testimony by criminalist Henry Lee. Court will be dark today to give the defense time to edit the videotape of Lee’s testimony. The trial will resume Monday at 8:30 a.m.