A former chemist in the Prince George's County drug lab who alleges widespread irregularities at the lab and is suing the county for firing her cannot call a forensic sciences expert in her lawsuit against the police department and the county.

A U.S. magistrate has ruled that Kellie Lynn Campbell cannot introduce testimony from Walter F. Rowe, a widely respected professor of forensic sciences at George Washington University, in her case. Campbell alleges in her federal civil rights lawsuit in U.S. District Court in Greenbelt that she was fired in March because she tried to speak out about problems in the drug lab.

U.S. Magistrate Judge Charles B. Day ruled late last month that Rowe's testimony would not be relevant to Campbell's lawsuit challenging the county's decision to fire her.

Campbell wants to have Rowe testify to bolster her credibility about her allegations that the drug lab is plagued with problems. The problems, she said, have called into question the lab's analysis of drug samples, potentially casting a shadow on prosecutions that relied on the lab's data.

The public defender's office is seeking postponements in more than 100 drug cases, arguing to judges that prosecutors should have made the defense lawyers aware of Campbell's allegations.

In his two-page ruling, Day wrote that Rowe would "apparently corroborate [Campbell's] contentions that there were a host of problems regarding the standard operating procedures within the police crime lab." Despite that, the magistrate found that "this corroboration is an immaterial point" in the lawsuit alleging wrongful firing.

The magistrate wrote that court papers filed by both the county attorney and Campbell's attorneys tell a different story. They "repeatedly highlight" that Campbell was fired because officials determined that she lied to county prosecutors in November 1998, when she told them that lab manager John Porter ordered her to sign a drug analysis report she said she knew was faulty, Day wrote.

At the time, Campbell also told prosecutors that there were widespread problems in how drug lab equipment was calibrated and that many other test results were unreliable.

After Campbell made her allegations, county prosecutors dropped the charge against the defendant in the drug case in which Campbell had been scheduled to testify. Police internal affairs investigators later determined that Campbell had lied to prosecutors and failed to prepare for the drug case in which she was scheduled to testify.

In his ruling, Day wrote that county attorneys noted that Campbell's firing was not related to how she performed the drug analysis. Rather, he wrote that she was fired because she certified a drug analysis report and then told a prosecutor on the day the trial was scheduled to begin in that case that she could not vouch for that analysis.

The ruling effectively means that Campbell's attorneys will not be able to call an expert to testify if her civil case goes to trial, since the deadline has passed for them to obtain an expert in the case.

John Bielec, deputy county attorney said, "The county is pleased with the court's ruling."

In court papers, county attorneys had argued that expert opinions about any deficiencies in the police drug lab would not be relevant to Campbell's case.

"The use of this expert is just an attempt to cloud the issues by raising inflammatory and irrelevant matters before this court in the hopes of prejudicing the court and/or jury against the defendants," Assistant County Attorneys Rhonda L. Weaver and William A. Snoddy wrote.

"There is no connection between the procedures of the drug analysis lab and plaintiff's claims. This is an employment case. Issues concerning the standards and policies of drug analysis in the lab are not relevant," Weaver and Snoddy wrote.

Campbell's attorneys, Eric L. Siegel and Francisco J. Ruben, had argued in court papers that Rowe's expertise was relevant to their case and would bolster Campbell's credibility.

Campbell's "expert is relevant to enhance the credibility of Ms. Campbell in general. The fact that her protests regarding problems in the drug analysis laboratory are true will carry substantial weight with the trier of fact when determining whose testimony to believe," Siegel and Ruben wrote.

The county's "incredible assertions that global problems in the drug analysis laboratory did not, and do not, exist should be put to the jury for its assessment of witness credibility," Siegel and Ruben wrote.

No trial date has been set for Campbell's lawsuit.

In the meantime, the county public defender's office is asking judges for postponements in more than 100 drug cases, arguing that prosecutors should have notified them about possible problems in the police drug lab.

In August, Circuit Court Judge E. Allen Shepherd rejected a request by the public defender's office for detailed information on the practices of the drug lab.

State's Attorney Jack B. Johnson has said that he has taken police at their word that the lab's practices and drug tests are sound.

The lab, at police headquarters in Landover, tests samples in about 3,000 cases a year, according to police. The state's attorney's office prosecutes felony drug cases and about 6,000 misdemeanor drug cases annually.