A Prince George's County judge yesterday rejected a public defender's request for information on whether police botched drug tests used in criminal cases. The judge said he first wanted to hear from the chemist who made the initial complaints.

Circuit Court Judge E. Allen Shepherd ruled that the public defender's office had to produce former police lab employee Kellie Lynn Campbell in order to proceed with its motion. It was Campbell's allegations about irregularities in drug testing that led four assistant public defenders to seek information about lab practices as part of the 90 adult and juvenile drug cases they are now handling.

"We're not going to proceed beyond this point unless you produce Kellie Lynn Campbell," Shepherd said, adding that Campbell's claims are "the whole basis of the motion."

County Public Defender Joseph M. Niland said he did not subpoena Campbell or request that she appear at yesterday's hearing because there was no legal need to do so. He said he may seek to have her testify later.

Some of Campbell's claims have been buttressed in a report submitted by Walter F. Rowe, a professor of forensic sciences at George Washington University, that is now part of the file in Campbell's civil case.

Campbell is suing the county, alleging she was fired from her job as a chemist in March because she spoke out about problems in the lab. She hired Rowe as an expert witness. He found serious problems in the standards and procedures used by the police drug lab, which call into question the validity of test results.

Defense attorneys, prosecutors and police officials packed yesterday's hearing room because of the high stakes involved: Hundreds of drug cases could have been in jeopardy because of Campbell's allegations.

After meeting with Campbell in recent weeks, Niland alleged that prosecutors knew of possible improprieties in the police drug lab dating from November, when Campbell came forward with her allegations.

Niland accused prosecutors of failing to notify defense attorneys about the allegations as they are required to by law.

Moments after Shepherd's decision, State's Attorney Jack B. Johnson, who attended the hearing, said: "I'm disgusted, and really insulted, that these allegations keep coming in without any basis. To make broad, sweeping allegations accusing us of impropriety is outrageous. The judge is absolutely correct."

Niland later shot back: "We are entitled to challenge the conclusions of anyone in the lab. How can we do that without having access to the information they relied on to reach their conclusion? I think it's so simple, it's over his [Johnson's] head."

The public defender also criticized the judge's ruling. "As far as I'm concerned, this was a non-hearing," Niland said.

"He's going to tell us who we have to call as witnesses? Where's he coming from? He doesn't have any right to tell us how to put on our case."

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 about 1,200 felony drug cases and about 6,000 misdemeanor drug cases annually.

Campbell was scheduled to testify in a drug case last Nov. 4, according to her lawsuit against the county.

Just before the trial began, Campbell told three prosecutors that she could not vouch for the test results showing the substance in question was cocaine, and she also reported problems with other test results, according to the lawsuit.

Campbell told prosecutors that, from March through July, lab director John Porter improperly calibrated various pieces of forensic equipment, making the drug analysis results unreliable in many instances, and refused to acknowledge any of the equipment had malfunctioned, according to Campbell's lawsuit.

Porter had ordered her not to re-test any drug samples, according to Campbell's lawsuit.

Prosecutors dropped the drug case Campbell was scheduled to testify in. Police internal affairs investigators eventually found Porter had committed no wrongdoing and determined that Campbell had lied to prosecutors and had failed to prepare for the drug case that was dropped.

Although Campbell hopes to use the report of Rowe, the George Washington University professor, to support her case, county attorneys have requested that U.S. District Judge Alexander Williams Jr. exclude him as an expert witness.

County attorneys did not challenge Rowe's findings but wrote that his report is not relevant to Campbell's lawsuit alleging employment discrimination and violation of her First Amendment rights.