A police technician could have contaminated blood evidence in the O.J. Simpson case when she used dirty tweezers to collect crime-scene samples, a scientific expert testified for the defense.
Microbiologist John Gerdes acknowledged, however, that except for a couple of tests, he had "no direct evidence" of actual contamination, only of risky collection techniques and unusual results.And as for those questioned tests - on blood in Simpson's Bronco and on a blood drop near the bodies of Nicole Brown Simpson and Ronald Goldman - Gerdes backpedaled, noting that other tests validated these results.
Asked specifically during cross examination whether it appeared the Bronco blood test was contaminated, Gerdes said, "Yeah, I guess you could say that."
Questions from plaintiff attorney Tom Lambert at the wrongful death trial Thursday followed the defense's attempt to sketch out an ominous scene of a messy police lab.
Defense lawyer Robert Blasier played a videotape, with narration from Gerdes, of a police technician haphazardly collecting blood samples.
The video - produced by prosecutors in Simpson's criminal trial to demonstrate police efficiency - shows Andrea Mazzola swabbing up blood drops while leaning a gloved hand on dirty ground, touching tweezers with the same hand, then using the tweezers to manipulate a bloody swatch.
"I'm sure she's not aware of it," Gerdes testified. "Everything that's been brushed around with her hands (on the ground) is now on the tweezers."