A prosecutor in the drug and perjury trial of D.C. Mayor Marion Barry said in court yesterday there was "absolutely no truth" to an assertion by Barry's lead attorney that the FBI had an "assault force" of FBI agents that roamed the country targeting black elected officials.

Assistant U.S. Attorney Judith Retchin, addressing U.S. District Judge Thomas Penfield Jackson out of the presence of the jury, also denied Mundy's allegations that several female FBI agents turned down an undercover assignment at the Vista Hotel sting because they found it "morally repulsive," and that the FBI offered money to six women before former Barry girlfriend Hazel Diane "Rasheeda" Moore agreed to lure him to the hotel.

Mundy responded in court yesterday by repeating his accusations, saying he had five sources to back up his statements he had made Thursday at a bench conference, out of jurors' earshot.

His main allegations -- later echoed by Barry -- was that the lead FBI agent on the Barry case, Ronald Stern, "moves around the country as the head of an, in effect, assault force of FBI agents" who single out black elected officials around the country. Mundy said that in addition to the sting of Barry, Stern had been involved in undercover operations against black elected officials in Atlanta and Chicago.

Mundy provided few details about the investigation and provided the names of only two officials -- former Atlanta Mayor Andrew Young and former Georgia state legislator Julian Bond -- against whom Mundy said Stern had tried to set up another undercover operation. Outside the courtroom Thursday, Mundy additionally alleged that Stern had participated in something called "Operation Coffee-Klatch" in Chicago. It was a probe of alleged ties between organized crime and politicians.

Law enforcement sources joined Retchin yesterday in vehemently denying Mundy's assertions, and they pointed out what they described as key factual flaws in his accusation. They said that Stern is a line FBI agent with no supervisorial rank, that he has played an important role in several investigations of white officials, that he was not an FBI agent in Chicago and was not involved in "Operation Coffee-Klatch."

The officials said Stern was a deputy U.S. marshal in Chicago and that his first posting as an FBI agent was in Atlanta. They said he was transferred to Washington about three years ago in a routine move to join the public corruption unit here, in large part to investigate abuses at the U.S. Department of Housing and Urban Development.

In Atlanta, they said, Stern was one of the lead undercover agents in "Operation Nickelride," and that his work in that case led to the conviction on drug charges of Leroy Stynchcombe, the chief deputy sheriff of Fulton County, who is white.

Officials in Atlanta said yesterday that even though there was an investigation in 1987 of Young and Bond -- which yielded no charges -- Stern was not a lead agent on the case. Mundy was incorrect when he stated that law enforcement officials carried out or planned an undercover sting of Young and Bond, the officials said.

"That's absolutely false," said Robert Barr, the U.S. attorney in Atlanta at the time of the investigation there, of a planned sting. "It's also important for people to realize the investigation began as an Atlanta police investigation. We, the feds, became involved when we were asked to become involved by the local police."

Barry has consistently argued that his indictment and prosecution is the result of overzealous federal investigators who singled him out because he is a leading black elected official. Federal officials repeatedly have denied the accusation, and said the Barry investigation grew out of numerous allegations about chronic drug use by Barry.

Law enforcement officials also pointed out yesterday that blacks were in key decision-making positions at critical periods in the Barry investigation, including D.C. Police Chief Isaac Fulwood; Edward S.G. Dennis Jr., the head of the Justice Department's criminal division; Tom Jones, the deputy assistant director of the FBI's white-collar crime division; William Martin, until recently third in command in the U.S. Attorney's Office here; and Richard W. Roberts, the other lead prosecutor on the Barry case.

"What we would be prepared to prove," Retchin told the jury yesterday, "is that there was absolutely no truth to the allegation that there is an FBI task force or any group of any sort within the FBI that has targeted black officials."

Retchin also denied Mundy's assertions made Thursday that several women friends of Barry's had been offered and refused money to participate in an undercover operation against the mayor. Retchin also disputed Mundy's allegation that several women FBI agents refused to take part in the operation before agent Wanda King -- using the pseudonym Moore -- agreed to take the role of Rasheeda Moore's drug-selling friend.

Retchin said King was the "first and only female FBI agent asked to participate in the undercover operation," and that "absolutely no witness, no witness has been offered monetary reward of any sort."

Mundy told the judge, "We just simply stand on the representations we made." Mundy did not identify the women or agents and did not name his five sources, but said they included an attorney for a prosecution witness in the Barry case; a person to whom Stern "in an unguarded moment" discussed "his activities mentioned;" a former FBI informant; an attorney for a person who spoke to investigators; and a letter that Mundy said made "certain representations."

Under the legal canon of ethics, an attorney must have a "good-faith basis" to make the kind of proffers, or representations, he has made in court about the FBI.