For D.C. police, the break came when a whispered voice on the telephone gave them the name of a suspected heroin dealer near 10th and P streets NW.

Armed with the name and a search warrant, officers went to 1003 P St., arrested the suspect and along the way seized nearly five pounds of heroin -- a massive cache with a street value of about $7.7 million.

The spectacular bust in August 1983 resulted from an anonymous tip telephoned to the D.C. police department's Crime Solvers office, a privately funded, nonprofit project similar to several others in the Washington area that pay up to $1,000 in rewards to citizen tipsters whose information leads to the arrest and indictment of suspects in crimes ranging from murder to drug pushing.

All told, since it started the program in July 1981, D.C. police Crime Solvers has paid out $20,800 in cash rewards -- just part of more than a quarter-million dollars Crime Solvers has distributed as far back as 1978 through several participating police departments in the area.

According to figures supplied by police in D.C., Fairfax County, Alexandria, Montgomery County and Prince George's County, citizen tipsters have helped solve 2,346 criminal cases and brought about the arrest of more than 1,000 suspects since the programs began.

Crime Solvers programs -- there are dozens in the mid-Atlantic region and reportedly more than 400 in the United States and Canada -- are each operated autonomously by a volunteer board of business persons and community activists who raise reward money through private contributions and channel the funds to the police department in their jurisdiction for payments to tipsters.

The police departments in turn publicize major unsolved cases through television spots and news releases, offering not only up to $1,000 in cash but also complete anonymity to all tipsters.

The tipsters' calls are handled only by police officers who take their information. Tipsters are not required to give their names or other identifying information. Each is given a caller number for identification purposes in future contacts. If a tip leads to an arrest and indictment, the tipster is given his or her reward usually by meeting a member of the Crime Solvers civilian board at a predesignated location, such as a doorway to a busy downtown store. The tipster knows the board member's name, but the board member knows the tipster only by this caller number.

"Anonymity, that's the key to the program," said Officer George Ludington, coordinator of the Montgomery County program.

"It's been working pretty good," says D.C. police spokesman Sgt. Joe Gentile. "It's cost-effective," said fellow Officer Rufino Fisher in the D.C. program.

But even with the lure of cold cash, Fisher added, some tipsters don't step forward to accept it. "Believe it or not," he said, the tipster in the $7 million drug bust in 1983 "did not call back for the $1,000 reward . . . . Some people just want justice."

Other noted cases in the Washington area recently did result in reward payments. Ollin (Renee) Crawford, convicted last fall in the five so-called "grenade lady" robberies in Fairfax County, was arrested after an anonymous tipster called county police and provided the name of the suspect in the long-unsolved robberies.

With her name, investigators obtained her picture from another law enforcement agency, says Fairfax County Police Crime Solvers coordinator Officer Terri McDaniel. Several witnesses in the robberies identified the woman in the picture as the robber who entered five Fairfax County banks during a three-month period, demanding money and claiming to have a hand grenade in a sock. Crawford was arrested in Laurel, convicted and sentenced in March to 70 years in prison. The anonymous tipster received $1,000 cash.

Still unsolved is the slaying of Hye Ja Yi, an 18-year-old Korean-born Gaithersburg High School student found beaten to death April 30 at a construction site near her home in Montgomery County.

County police publicized the case as the "Crime of the Week" last week, sending pictures of the woman and other data to local television stations and newspapers and offering a $1,000 reward for information leading to an arrest and indictment in the case. The $1,000 Crime Solvers reward has been supplemented by an offer of $10,000 from the family and friends of the slain woman and another $1,000 from the Gaithersburg and Upper Montgomery Chamber of Commerce.

Who calls in tips to police about murderers, thieves and assorted other miscreants? "Most of them are people who have heard these jerks running at the mouth, bragging somewhere," said Prince George's County Crime Solvers coordinator Officer Carol Landrum.

Also, said Officer John Kochensparger, coordinator for the Alexandria police, the tipsters often are the "fringe element between the criminals and law-abiding society . . . .Theirs is the best information."

He said, "I've had calls where the actual suspect was in another room" next to the tipster, and the tipster would "mumble and talk low."

Kochensparger said the percentage of men and women among tipsters "is split down the middle." Women, he said, often "will call on a boyfriend or a husband" if they have broken up. "They call out of the circumstances of the lives . . . whereas the men usually call about something they've heard." The telephone number for confidential calls to D.C. Crime Solvers is 393-2222.