The Prince George's County prosecutor who dropped a drug case in November after a police chemist said she could not vouch for the drug analysis in that case testified in a civil case deposition that she believed there may have been problems with test results in other cases.

Assistant State's Attorney Toni Drake said the chemist, Kellie Lynn Campbell, told her that the laboratory device used to test for cocaine may not have been calibrated correctly and also that cocaine residue may have produced false readings in other cases. Drake said Campbell told her that she had retested results in those cases.

Campbell's allegations of misconduct at the Prince George's police lab are at the heart of a controversy involving scores of drug cases. The county public defender's office has asked for trials in dozens of cases to be postponed, saying that prosecutors should have disclosed possible problems.

So far, the efforts have been unsuccessful. Last week, Circuit Court Judge E. Allen Shepherd dismissed the public defender's request for the state's attorney's office to produce detailed information about the police drug lab, its equipment and its chemists, saying he would have to hear from Campbell.

Yesterday, Circuit Court Judge G.R. Hovey Johnson turned down a motion seeking a hearing on the drug lab issue in a drug case scheduled for trial tomorrow.

But Public Defender Joseph M. Niland has vowed to continue filing motions seeking information on the drug lab with each judge in each case.

In an Aug. 13 deposition, which Drake gave as part of a federal civil lawsuit Campbell is pursuing against the police department for firing her in March, the prosecutor said she believed there might be problems with other analyses by the drug lab.

"Just the issue of the calibration of the machine, and her retesting other cases, so from that, I think that there were other cases that were involved," Drake testified, according to a transcript of her deposition obtained by The Washington Post.

Drake said she knew Campbell to be professional and truthful, according to the transcript.

State's Attorney Jack B. Johnson said yesterday that Deputy State's Attorney Mark K. Spencer and other top prosecutors met with lab manager John Porter and other police officials Nov. 5, the day after Campbell made her allegations. Prosecutors were assured that the lab's test results and practices were sound and took police at their word, Johnson said.

"Our office was assured that the lab was running well and any problems in the lab stemmed from Kellie Campbell, not the lab itself," Johnson said. "I didn't ask for an independent audit. I take the police department's word for everything in terms of the evidence we use."

Campbell's lawsuit, filed in U.S. District Court in Greenbelt, alleges that she was fired because she tried to speak out about problems in the lab.

A police internal affairs investigation determined that Campbell lied to prosecutors and police investigators and failed to prepare for a drug case assigned to her for trial.

County Attorney Sean Wallace, whose office is defending the police department in Campbell's civil suit, said Campbell's allegations are "baseless and not to be believed."

When Campbell said Nov. 4 that she could not vouch for the results of her tests, Drake asked a Circuit Court judge to dismiss a charge of possession of cocaine with intent to distribute against Curtis Anthony Scott, according to the deposition transcript.

Drake said she did not make defense attorneys aware of Campbell's allegations because "I personally would not want defense attorneys to think that there was a problem in the lab, because then they would attack the cases not on the merits, but on what they perceived as something going on in the drug lab per se."

Assistant Public Defender Janet Hart, who represented Scott, said yesterday that Drake did not say why she was dropping the charge against Scott. Taking issue with Drake's rationale for not making defense attorneys aware of Campbell's allegations, Hart said, "Whether the substance is cocaine is a substantial part of the case."

CAPTION: Public Defender Joseph M. Niland has asked for trials to be postponed.