The charges against nearly one-third of the 71 suspects arrested since January by D.C. police undercover officers posing as drug dealers have been dropped, and none of those convicted has been ordered to jail, according to court records.

The charges against 23 defendants, who were arrested for possession of Dilaudid or Preludin -- presceiption pills commonly used on the streets as heroin substitutes or boosters -- have been dropped for insufficient evidence or because they were first offenders and were allowed to participate in drug treatment or community service programs. Nine persons have been convicted and received fines, suspended jail terms or probation or both.

Nine other defendants are being sought on bench warrants for failure to appear for court hearings. The cases of the 30 remaining suspects are still pending.

The 71 arrests have resulted from the police department's Operation Bamscam, named after "bam," the street term for Preludin. The operation, which is continuing, involves the use of undercover police officers primarily in the Ninth and O streets NW area, a popular center for the sale of illicit prescription drugs.

"We didn't expect anybody to go to jail," said Inspector Kris Coligan, head of the police department's morals division. "We weren't that naive. . . . Hopefully the chances of being arrested will deter them and others."

"The question is are you creating an understanding in the relevant community that you buy drugs in the city at a risk?" said U.S. Attorney Charles F. C. Ruff. He contends that is being done.

"A great number of the individuals arrested were first time offenders," Ruff said, explaining that first offenders often are not given prison time and are diverted into drug treatment or community service programs.Eleven Bamscam suspects have been diverted.

James N. Owens, assistant U.S. attorney in charge of the misdemeanor branch at D.C. Superior Court, said that when a person successfully completes the three-month drug treatment program or the 20-to-40 hours of community service, the charge is dropped.

Ruff said the fact that defendants are placed in a diversion program should not be taken lightly since they are brought into court and made aware that they have "committed a crime."

Charges against 12 Bamscam defendants were dropped immediately because of a lack of evidence, according to police and prosecutors who declined to give specific reasons. However, one suspect arrested for possession of a Dilaudid pill said the charge against him was dropped because he had swallowed the pill.

Despite the dropped charges and lack of prison sentences, Ruff said Bamscam "is worthwhile."

D.C. Police Chief Maurice T. Turner said, "We are going to keep on locking them up. We are doing our job."

Of the 71 persons arrested since Jan. 22, police say 51 have been whites and 50 were from the suburbs surrounding the District, indicating that commuters and outsiders play a large role in the city's illegal pill trafficking.

Officials estimate that 50 percent of the buyers of illicit prescription pills throughout the city are suburbanites.

More than a dozen of those suburbanites said in interviews that marijuana, cocaine and a few other drugs are easy to obtain in the suburbs. But most drug users depend on D.C. street pushers for heroin, Dilaudid, a synthetic opiate sometimes called "hospital heroin," and Preludin, a diet pill.

The penalties for the nine defendants convicted in the Bamscam operation have ranged from as little as a $50 fine up to a $300 fine plus a one-year suspended prison sentence and two years probation.