A federal jury completed its first full day of deliberations yesterday in the cocaine and perjury case against D.C. Mayor Marion Barry, and will resume its deliberations today for up to four hours.

Near the end of the day, the 12-member panel sent a note to U.S. District Judge Thomas Penfield Jackson asking to view two prosecution exhibits: a time chart detailing the months in which some witnesses testified that Barry possessed cocaine, and the cooperation agreement between the government and prosecution witness Doris Crenshaw.

Crenshaw, a Barry friend since their days in the civil rights movement, testified that she and Barry used cocaine together more than a dozen times since 1984, including during the 1988 Democratic National Convention in Atlanta. Her testimony additionally forms the basis for count 12 of the 14-count indictment.

Crenshaw, a former deputy campaign manager in former vice president Walter Mondale's presidential campaign, testified under a limited form of immunity known as "use immunity," which prohibits the government from using her statements against herself in any future investigation.

R. Kenneth Mundy, Barry's attorney, told reporters that he thought the request meant that she was the "only {witness} they found credible." Other lawyers, not associated with the case, cautioned against reading too much into the jury note.

"It is very difficult to predict what the jury is discussing when they send out notes," said criminal defense lawyer Bernard S. Grimm, formerly with the D.C. Public Defender Service. "I have had notes that I thought predict favorably for me and predicted against me, and the verdicts have gone either way."

Grimm disagreed with Mundy's interpretation of the request to see the cooperation agreement between Crenshaw and prosecutors. "It may mean someone feels badly about her," Grimm said.

G. Allen Dale, another criminal lawyer, also said it was difficult in most cases to interpret juror notes, but he said in a case such as this, in which the foreman is a schoolteacher, "it would tell me they are at count 12."

Foreman Edward Eagles, a 54-year-old history teacher at St. Albans School, is responsible for supervising the direction of the deliberations.

"This guy is going to go back there and organize things one count at a time," Dale said. "This would tell me they are moving fast, a lot faster than I thought they would."

Also at yesterday's afternoon hearing, Mundy told Jackson about media reports that an unrelated undercover drug operation was conducted Thursday night in the parking lot of the Prince George's County hotel in which the Barry jurors were staying.

In the middle of the aborted drug sting, one of the sting's targets -- Brian Lee Tribble, who was acquitted of supplying the cocaine that killed University of Maryland basketball star Len Bias in 1986 -- escaped from federal drug agents at the Sheraton Inn in New Carrollton, authorities said. Earlier, agents from the Drug Enforcement Administration had arranged to sell Tribble a kilogram of cocaine, they said.

The judge said he had been informed by an official of the U.S. Marshals Service that the jurors "were oblivious to the event that took place." Mundy said he would like the judge to question each juror to determine whether they know about the incident.

U.S. Marshal Herbert M. Rutherford said yesterday that the jurors were unaware of the undercover operation, but provided no further details. Mundy said he was told the jurors had been moved to a new location.

Jackson also turned down a request from defense attorneys Mundy and Robert W. Mance to give the jurors a special verdict form that would require the jurors, in the event they return a guilty verdict on any of the three perjury counts, to identify the false statements the mayor made to the grand jury.

The defense attorneys made a similar request for the conspiracy to possess cocaine charge, asking that the jurors identify who, among the 20 or so alleged co-conspirators, they believed comprised the conspiracy.

The defense attorneys said having such a special verdict form, naming co-conspirators, would make it easier for them if there were an appeal of a conviction. The judge, citing a precedent in an appellate court decision involving former national security adviser Oliver L. North, said it was unnecessary because he had instructed the jurors that they had to have a unanimous agreement on the identity of the co-conpsirators and the false statements.

Meanwhile, sources said yesterday that the light bulb used by prosecutor Richard W. Roberts in his closing arguments Thursday came from Room 902 at the downtown Ramada Inn and was removed during a lunch break before his presentation to the jury. Mundy had shown the jury a much larger bulb the size of a softball in his closing argument and said it resembled the one that prosecution witness Charles Lewis testified that Barry stuffed into his suit jacket in a moment of paranoia about surveillance equipment.

Staff researcher Ben Iannotta contributed to this report.