A videotape of a police technician haphazardly collecting blood samples drew gasps at O. J. Simpson's civil trial today, and a DNA expert testified for the defense that the DNA evidence collected had probably been contaminated and made worthless.
But the witness, John Gerdes, a microbiologist, conceded under cross-examination, that with the exception of a couple of samples, there was ''no direct evidence'' of contamination, only risky collection techniques and unusual results.
The video had been produced by prosecutors in Mr. Simpson's criminal trial to demonstrate police efficiency. It shows the technician, Andrea Mazzola, swabbing up blood drops while leaning a gloved hand on ground, touching a tweezers with the same hand, then using the tweezers to manipulate a bloody swatch.
''I'm sure she's not aware of it,'' the microbiologist, John Gerdes, testified, but ''everything that's been brushed around with her hands is now on the tweezers.''
Ms. Mazzola, who testified earlier this week, was shown failing to change her gloves between handling of samples, placing wet swatches in plastic bags where Mr. Gerdes said bacteria could grow and cleaning the tweezers by merely wiping them with clear water.
''As sensitive as this process is, you should use a new sterile instrument,'' Mr. Gerdes said. ''She uses water, and you can't get DNA off with water.''
There were muffled gasps in the courtroom as the tape played. Several jurors leaned forward to get a better view and took copious notes as Ms. Mazzola brushed her hand across the ground as if to clean it off.
While questioning Mr. Gerdes, a lawyer for Mr. Simpson, Robert Blasier, pressed his point that sophisticated DNA results from two highly respected laboratories were worthless because they were based on such contaminated samples.
Mr. Simpson was acquitted of killing his former wife, Nicole Brown Simpson, and Ronald L. Goldman after defense lawyers based much of their case on the DNA contamination theory. The victims' families are suing Mr. Simpson for wrongful death.
A new team of lawyers is following closely in the footsteps of the criminal defense team, which suggested that a false case had been built against Mr. Simpson as the result of police conspiracy and evidence contamination..
Mr. Blasier, the DNA expert on the new the defense team, used Mr. Gerdes's testimony to advantage in spite of a ruling by Judge Hiroshi Fujisaki of Superior Court that Mr. Gerdes could not testify in general about DNA contamination in the Los Angeles police laboratory. Mr. Blasier limited his questions to the Simpson evidence.
Mr. Gerdes also noted that Collin Yamauchi, a laboratory technician, had processed 23 DNA samples in one day. ''It's a very laborious, tedious process,'' Mr. Gerdes said. ''It could take all day to do four items. Twenty-three samples in one day is a tremendous number of samples.''
Mr. Gerdes came under immediate attack by a lawyer for the plaintiffs, Tom Lambert.
Mr. Lambert noted that Mr. Gerdes had never collected or processed evidence from a crime scene. Mr. Gerdes also conceded under cross-examnation that he had appeared in court 35 times, always for the defense, and had always concluded that the DNA results were unreliable.