BALTIMORE, JULY 7 -- A Baltimore County police officer accused of using his girlfriend to tip alleged drug dealers about police surveillance was arrested Monday and charged with conspiracy to distribute cocaine, federal and local narcotics agents announced.

Ronald Stephen Edwards, 26, a uniformed member of the county force for five years, was arrested as he began his regular duty shift in Towson in suburban Baltimore.

"He was slipping information to his girlfriend," said an agent of the federal Drug Enforcement Administration. "He would pass stuff on he heard on the grapevine. He was using his office."

According to papers filed in federal court, Edwards passed on information about both county and federal narcotics surveillance to a woman identified as Kimberly Ann Gill, 24, of suburban Parkville. The papers identified Gill as Edwards' girlfriend.

Gill is accused of passing the information on to her brother and others allegedly involved in drug deals. Gill also was arrested and charged with conspiracy. In addition, police were still looking today for Gill's brother, Gregory Michael Gill, 21, also charged with conspiracy in the case.

According to court papers, suspicion focused on Edwards after special DEA task force agents arrested a suspect leaving an Amtrak train in Baltimore last month and seized 11 ounces of "high-grade" cocaine from him.

The unidentified suspect began cooperating with investigators, the court papers said, leading police ultimately to Gregory Gill who allegedly was to receive the bulk of the 11 ounces of cocaine.

According to the papers, agents recorded several telephone calls with the consent of the unidentified suspect and a second informant in which they talked with both Edwards and the Gills. In one call, Edwards indicated he was aware of the cocaine transaction and "counseled {the informant} on police procedures and methods in avoiding detection and disposing of narcotics and documents relating to their narcotics distribution activities," according to the court papers.

The case against Edwards and the Gills will be presented to a federal grand jury here in the next few weeks. If indicted and convicted, each could receive a maximum sentence of 20 years.