D.C. police mounted a full-scale investigation yesterday into the false report carried by four local television stations that Mayor Marion Barry was shot Monday night. Investigators were sifting through scores of leads, dusting for fingerprints on telephone booths and interviewing reputed hoaxers and harassers of public officials.

At the same time, those television stations that had broadcast the phony report were publicly explaining their premature actions -- which briefly created pandemonium before the mayor was found to be unharmed -- and were privately analyzing ways to minimize them in the future.

"Maybe the best thing we [broadcast journalists] can do is to slow the process so that we don't concern ourselves as much with being first," said David Nuell, news director of WRC-TV (Channel 4), the first station to air the report.

Jack Smith, Washington bureau chief of CBS News, said the incident should reinforce "the basic tenet of journalism: you have to establish the fact before you report it."

Police officials late Monday and early yesterday marshaled more than a half-dozen detectives in the department's investigative services division to start tracking down the mysterious "James Taylor" who called local TV stations Monday night posing as a city government official with the report that the mayor had been shot on the front lawn of his home and was being rushed to the hospital at nearby Andrews Air Force Base.

By late yesterday, police said they had a number of possible suspects supplied by interested citizens, but had not yet narrowed their field to an individual.

There was one other small bit of forward motion in the investigation: The voice of the "James Taylor" who called the television stations matches the recorded voice of a man who called in a false fire alarm to the Fire Department at about the same time the phony shooting was reported.

All calls to the Fire Department are taped, and WRC-TV anchorman Marty Levin yesterday identified the voice on the tape as the same one that called the TV station.

The caller, who was "articulte, intelligent and responsible-sounding," according to Assistant Police Chief William Dixon, placed several calls from at least two pay phones on the Mall and claimed variously to be a mayoral assistant and a staff worker in the mayor's command center.

Technicians traced the calls to the Mall telephones yesterday and dusted both for fingerprints. Officials said they obtained some prints but would not say what if any significance they had. One of the phones is located just south of the National Gallery of Art on Madison Drive. The other is adjacent to the skating rink near the Museum of Natural History.

Other detectives interviewed scores of tipsters and began contacting persons reported to be chronic hoaxers and disgruntled individuals known for attempting to harass or intimidate public officials, including Mayor Barry.

A police spokesman said that the hoaxer, if caught, may be subject only to a minor technical charge, such as placing a false firm alarm, but "at a more serious level, we are concerned that he may be a danger to the mayor."

Officials at the three television stations yesterday attributed the mistake to the intense competition between stations, the importance of being first with the story in the instantaneous world of electronic journalism, and the "media snowball" that devloped after the story first hit the air on WRC-TV (Channel 4).

"The climate has been created that it's important to be first," said Barbara Holtzberg, a spokesman for WRC-TV. But officials at all three stations defended their decisions to broadcast the story.

Both WRC and WDVM-TV (Channel 9) went with the story after news personnel got what they thought were solid confirmations that later turned out to be bogus, according to officials at both stations.

Levin, the WRC anchor who was the first to go on the air with the story at about 9:50 p.m., said he broadcast the report because producer Wendy White told him that she had received confirmation from the mayor's command cente. "Under that circumstance," he said, "I had no reason to doubt her."

In fact, she had simply called back a number left by the man claiming to be a mayoral aide. That number turned out to be in a phone booth.

"In the heat of the moment we though we were being very responsible," Levin said.

At WDVM-TV, where reporters learned of the shooting story from the WRC report, officials thought they had confirmed it when someone at the emergency room at the Andrews Air Force base hospital said the mayor had been shot and was on his way there, according to news director Betty Endicott. WDVM went on the air with the report about 10 minutes after WRC, she said.

Endicott said that the fact that police would not confirm the story did not cause the station to hold of because she said it is not unusual for authorities to withhold information in emergencies.

WDVM's story, based on the report from the Andrews hospital, served as the confirmation that caused both United Press International and CBS Radio news to transmit the story nationwide.

When CBS radio's Washington bureau could not confirm the WRC-TV report, it sought assistance from WDVM-TV, the CBS affiliate here, and was told that the Andrews hospital hd confirmed the story, according to Smith of CBS news. CBS radio then broadcast the story on its 10 p.m. network news, Smith said.

UPI reporters initially held back from reporting the story because they could not confirm it, according to Jeffrey Reynolds, UPI's Washington regional editor. However, "they made the mistake of turning on the tube and saw the damn thing all over the tube," Reynolds said.

He said the reporters then decided to go with the story and attribute it to WDVM-TV -- a violation of UPI's policy of getting independent confirmation in such stories, Reynolds said.

The story banged out on the UPI radio wire at 10 p.m.

The Associated Press, the other major national news service, did not move the story because it could not get confirmation, according to AP metro editor John Wilson. AP did move an account of the hoax at 10:34, however. e