It was a case for the Pill Patrol.

The owner of a Silver Spring drugstore telephoned Montgomery County police to report that in one year his pharmacist had typed more than 140 prescriptions for members of his family into the store's computer system.

Police said they believe that the 50-year-old pharmacist had bilked two insurance companies out of nearly $3,000 by submitting claims for false prescriptions that he had written. The Laurel resident was arrested last month and charged with theft and obtaining controlled dangerous substances by fraud.

It was one of an estimated 1,280 cases handled each recent year by the nine-year-old pharmaceutical section of Montgomery's special police investigations division. It is one of only two such squads in the state.

The section was formed in Montgomery in 1977 because there were so many complaints about prescription forgeries, according to the investigators. In Prince George's County, where no special unit exists, regular beat officers handle complaints involving prescription drugs, a county police spokesman said.

The Montgomery squad's four officers are among the the busiest of the department's dozen investigative teams, said detective F. Theodore Bryan, who heads the plainclothes unit. The four officers each handle nearly three times the average investigator's caseload, he said. Nearly 80 percent of the cases referred to the unit end in arrests, he said, compared with about 15 percent for buglaries, for example.

In another case handled by the squad, Robert Paul Thomas, 31, of Bowie was arrested last year after officers linked him to dozens of phony prescriptions that had been written for narcotics, including Demerol, a powerful painkiller to which he was addicted. On May 16 a Montgomery judge sentenced Thomas, who had three previous arrests, to 24 years in prison for faking prescriptions and distributing a variety of addictive drugs.

The judge suspended all jail time on the condition that Thomas attend a drug treatment program to kick his habit. On the second day of the program, District police arrested Thomas on similar charges involving prescription drugs. As of June he was in jail awaiting trial in the District.

Montgomery and Anne Arundel counties have the only police pharmaceutical units in Maryland, where it is a misdemeanor to forge a prescription. There is a similar division in the District, where prescription forgery is a felony.

The Montgomery unit often relies on tips from druggists who notice something amiss with a prescription.

In one recent case, for example, a pharmacist alerted the unit that he "You can't stand in a drugstore and say, 'Here comes an addict.' " -- detective F. Theodore Bryan had called to verify a narcotic prescription that had been called in, and found that the doctor was on vacation. Police arrested a man in the drugstore when he came in to pick up the pills.

Unlike heroin or cocaine addicts, who may have symptoms, people addicted to pills such as codeine, Dilaudid, percodan and Valium seldom show outward signs, the Montgomery investigators said.

"You can't stand in a drugstore and say, 'Here comes an addict.' You're going to see what looks like a high school student, then you're going to see a geriatric case coming in with a walker," Bryan said. They are "people who believe the pharmaceutical company ads that pills will solve all their problems."

People hooked on pills can be divided into several general types, according to the investigators: "Doctor shoppers" or "doctor hoppers" -- addicts who go to many doctors feigning pain in order to get prescriptions to satisfy their need for pills. For example, some addicts will have a tooth removed, then pick at the empty space in their gums and go to different dentist in search of prescriptions for painkillers, the investigators said. Health care professionals such as doctors, nurses, pharmacists, dentists and veterinarians who have ready access to prescription drugs and are under the illusion that they are immune to addiction. "Professionals -- doctors, nurses -- feel they understand the drug and they're not going to abuse it, they think," Bryan said. People with personality disorders such as anorexia nervosa, characterized by an aversion to food and an obsession with weight loss, who seek prescriptions for appetite suppressants and diuretics to speed weight loss.The rare case in which prescription drugs are both an addiction and a source of income. Hard-core heroin or cocaine addicts who rely on prescription drugs to get them through times when they cannot get their primary drug. "Each one's pathetic in their own right; each one's a different story," said Officer Tom Lester. "You've got the whole spectrum: There are professionals writing their own prescriptions, the ones who are in chronic pain, the bad addicts. You never hear of someone who's doing it for fun."