A Montgomery County Circuit Court jury ordered Peoples Drug Stores yesterday to pay $615,000 to a former teen-age sales clerk who charged that a company security investigator badgered her into falsely admitting that she pilfered $15 worth of merchandise.

Karen Reidy of Silver Spring, now a business student at the University of Maryland, was an 18-year-old part-time clerk at a Peoples Drug in Silver Spring in June 1985 when a security investigator accused her of stealing candy bars and other small items, according to her attorney, John J. Pyne of Chevy Chase.

Reidy, 20, alleged that the investigator detained her in a back room of the Georgia Avenue store for about 30 minutes after business hours on June 25, 1985, threatening her with jail, refusing to allow her to make telephone calls, and using other heavy-handed tactics to pressure her into signing an admission of guilt -- although she had stolen nothing, according to Pyne.

The questioning by Peoples investigators continued as Reidy's father knocked at the store's locked front door, Pyne said. John Reidy had come to drive his daughter home from work.

The jury, which heard three days of testimony beginning Monday and deliberated for three hours Thursday and yesterday, found that Peoples had falsely detained Reidy, but cleared the company of willfully inflicting emotional distress on her.

Pyne said he was pleased with the verdict. "I had thought down deep that they'd bring back a whopping verdict, but I wasn't sure how much," Pyne said. "You never know what juries will do in these cases."

He called Reidy, who was one of six clerks fired by the company in a theft investigation, "the most honest girl you'll ever meet."

A spokesman for Peoples said the company plans to appeal, and company lawyer James Schwarz said Peoples had no intention of changing security practices in light of the verdict.

"Our investigative practices are legal and proper and reasonable," said Joseph Pollard, vice president for public relations. "We just questioned her in the store."

But the jury saw it differently and awarded Reidy $200,000 in compensatory damages and $415,000 in punitive damages.

"We wanted to send Peoples a message that the tactics used were not acceptable," said one juror, who asked not to be identified. "We wanted them to know that something should be done about this."

The incident began when a team of Peoples security investigators conducted what they call a "shop test" on June 24, 1985, according to Pyne.

Two investigators picked a few small items from shelves and stood in line at the cash register, one behind the other, Pyne said.

After the clerk rang up the first investigator's purchase, the investigator stalled, fumbling in her purse as if searching for money, Pyne said.

After several moments, he said, the second investigator, acting annoyed at the delay, reached past the first investigator, dropped $3.14 for her purchase on the counter and left the store.

The first investigator, still fumbling in her purse, watched the clerk.

The clerk placed $1.14 in the cash drawer and $2 in his pocket, Pyne said.

Outside the store, the investigators told the chief investigator, Michael Moment, what they had seen, according to Pyne, who said Moment entered the store, summonded the clerk to a back room and began questioning him.

Pyne said the clerk -- and later, several others, including Reidy -- were questioned that night and the next night.

They later testified that Moment would not allow them to call lawyers or their parents, threatened them with jail, and harshly accused them of lying, taking money from cash registers, stealing merchandise and allowing friends to do so, Pyne said.

Pyne said the clerks testified that Moment falsely told them that the company had witnesses and videotapes of them pilfering goods.

Moment could not be reached for comment, and Peoples officials declined to discuss details of the case.

Peoples contended at the trial that some clerks implicated others in pilferage. But in their testimony, Pyne said, the clerks denied implicating one another.

Some of them in the past had indeed taken small items "without properly paying for them," Pyne said.

But, according to testimony, they were intimidated into admitting having taken much more, Pyne said.

Including Reidy, he said, six clerks signed statements acknowledging wrongdoing, and all were fired.

Reidy, who had been an employe of the store for two years, was questioned on the evening after the shop test and was told she could not leave until she admitted her theft in a written statement, Pyne said.

He said his client told Moment she had done nothing wrong.

The questioning continued past the store's 9:30 p.m. closing time, Pyne said.

He said Reidy eventually told Moment that although she could not recall precisely, she may have taken candy bars occasionally, intending to pay for them later.

Pyne said the admission was untrue and that Reidy had made it only because she wanted to go home.

Pyne said Moment allowed Reidy to leave about 10 p.m., after she admitted in a written statement that she had taken $15 worth of merchandise. Before she went home, she was fired.