D.C. Mayor Marion Barry is unlikely to testify in his cocaine conspiracy and perjury trial, his lawyer told U.S. District Judge Thomas Penfield Jackson yesterday.

The remark, made by defense lawyer R. Kenneth Mundy at a bench conference, could mean that Barry's defense will rest today after calling two or three final witnesses. If that happens, lawyers from both sides have said, the prosecution could complete its rebuttal by tomorrow and, after closing arguments, the case could go to the jury as early as Monday.

Meanwhile yesterday, a retired Army staff sergeant from the Virgin Islands, Albert E. Benjamin, testified for the defense that FBI agents and D.C. police investigators, questioning him about a 1986 cruise he took with Barry, tried to intimidate him into changing his story that he never saw Barry use drugs.

Mundy told Jackson he intends to call two law enforcement witnesses today, FBI Special Agent Ronald Stern and D.C. police Internal Affairs Division Sgt. James Pawlik. Mundy also has said he would like to call a forensic expert to testify about the effects of crack cocaine use on memory, but Jackson indicated he would prevent Mundy from doing so.

"I consider it right now unlikely that we will call Mr. Barry, but that is not something we have finally concluded," Mundy said at the bench conference.

As he left the courthouse yesterday, Barry declined to comment on his decision about testifying. Sources familiar with the case said Mundy has told prosecutors Barry will not take the stand.

For Barry, the decision of whether to testify has been a complicated one, but not a close one, sources said. The mayor has told associates that there were far too many witnesses who testified for the prosecution and far too many allegations for him to rebut.

Trial judges routinely admonish juries not to consider a defendant's decision not to testify, but trial lawyers generally believe that juries disregard such instructions. On the other hand, defendants risk dooming their defense with unconvincing testimony, lawyers say.

Sources said Barry's lawyers left the decision up to him, but strongly urged him not to take the stand.

Mundy's statement to the judge about the unlikelihood of Barry's testifying came late in the day, after testimony by Benjamin and his wife, Carmen.

Under cross-examination by Assistant U.S. Attorney Richard W. Roberts, Benjamin slightly softened his earlier statements that the FBI exerted undue pressure on him when he maintained that he hadn't seen drug use on the 1986 cruise.

Responding to Roberts's questions, Benjamin testified that FBI agents took him and his wife to dinner after one interrogation, and that the pressure he felt during the FBI interrogation was similar to the pressure of being a witness in a criminal trial.

The 55-year-old Benjamin, a resident of St. Thomas, described being flown to Washington with his wife by the FBI in late October 1989 and undergoing a five-hour grilling at FBI headquarters.

He and his wife were not allowed to talk to each other, and throughout, he said, Stern and Pawlik tried to get him to say that he had seen drug use by Barry on the cruise.

The agents, Benjamin testified, "kind of kept driving home the point that I had to know, I had to see, I had to be aware of, and just getting right down on top of you and just crowding you to the point that one time, and Officer Pawlik knows this, I told him in no uncertain terms, 'Mister, you have pushed your luck too far,' because it was too much pressure."

This testimony, as much as any in the trial so far, buttressed a key thought the defense has tried to get across to the jury: that investigators were overzealous and badgered witnesses to get them to make statements supporting the government's criminal indictment.

Later, Carmen Benjamin echoed some of her husband's account. She was prevented from testifying about the FBI interrogation in detail when Jackson ruled that that subject was irrelevant to Mundy's contention that similar FBI tactics had been used on other prosecution witnesses.

Carmen Benjamin testified that the FBI agents "were cordial, but they were kind of aggressive with us," and that at one point she demanded an end to the questioning. She was not allowed to testify that the agents stopped the questions when she offered to take a polygraph test to show that she hadn't seen drugs on the cruise.

The Benjamins' statements that they never saw Barry use drugs aboard the yacht Brigadoon might help rebut prosecution testimony by Charles Lewis, a former D.C. government employee who has provided much of the damaging evidence against Barry.

Lewis testified that he arranged the boat trip for Barry and Hazel Diane "Rasheeda" Moore during a June 1986 trip Barry made to the Virgin Islands. Lewis went on the cruise, as did a Lewis friend, Jonetta Vincent; plus Benjamin and his wife; and D.C. police Lt. Ronald Harvey, a member of Barry's security detail.

In his testimony, Lewis said that he provided powdered cocaine for the mayor and Moore, and that he used cocaine with Barry in the bathroom of the ship, below deck. Moore testified that she could not recall any cocaine use during that 1986 trip with Barry, but that she and Barry smoked marijuana on the craft that day. Vincent testified that Lewis offered her cocaine aboard the yacht, but that in the toilet she sneezed just as she was about to snort it. Vincent said she didn't see Barry use cocaine, but did see him smoke marijuana.

Under cross-examination by Roberts, Benjamin also said that he was not in a position to see Barry because he was so disgusted with Barry's sexual advances toward Moore that he tried not to look at the mayor.

Referring to Moore, he said that he saw some "overexposure" of her body. Barry, he said, "was making amorous advances toward her and she was accepting . . . . I was angry because I think adults should conduct themselves in a respectable manner in public."

He added that throughout the cruise, Barry, Moore, Lewis and Vincent made many trips from the upper deck to the cabin below. Roberts asked him whether all the movement had made him suspicious that they were taking drugs.

"I had a suspicion that there was something out of the ordinary going on in that boat," Benjamin replied. "I was not interested in trying to find out."

Testimony about the 1986 boat cruise is crucial to one of three perjury counts against Barry, which alleges that he lied to a grand jury in Washington when he denied knowing anything about Lewis's involvement with drugs. It also is relevant to the conspiracy count, which alleges that Barry conspired with Lewis and others to possess drugs between 1984 and this year.

Earlier in the day, Mundy recalled FBI Special Agent Frank O. Steele to testify at length about business cards and papers seized from Barry on Jan. 18, the night of his arrest in an FBI sting at the Vista Hotel. An FBI chemist testified that he found a residue of cocaine powder on the business cards.

In an effort to get the cards removed from evidence, Mundy tried to use Steele's testimony to show that agent Stern never actually handed the cards to him -- thus breaking the "chain of custody." Showing the chain of custody is required in criminal cases to introduce some items into evidence. Jackson, based on the testimony of Stern and Steele, has ruled that the cards are admissible.