Former D.C. Alcoholic Beverage Control board chairman Robert C. Lewis and his former aide James E. Boardley were convicted in U.S. court yesterday of bribery and conspiracy in connection with an alleged scheme to trade a liquor license for profits in a proposed liquor store.

Lewis and Boardley, accused of plotting with bar owner Tommy M. Motlagh to set up a liquor store at Hechinger Mall in which the officials would have hidden financial interests, sat expressionless at the defense table as the verdict was read, ending their two-week trial.

Both declined to comment on the verdict. Lewis' defense attorney, Robert Watkins, called the jury's findings inconsistent and said the bribery conviction was based on a convoluted indictment.

Lewis, a cabinet-level appointee of Mayor Marion Barry, and Boardley, whom Lewis appointed ABC staff director in 1979, were each convicted on separate federal charges of conspiring with Motlagh to commit bribery and of soliciting a bribe from a Hechinger employe who cooperated in a federal probe.

Prosecutors alleged that Lewis and Boardley planned to use their powerful government positions to guarantee Motlagh a liquor license over any opposition and to ensure that they received a share of profits from the store.

The jury, however, acquitted them on a federal charge of seeking or accepting a bribe from Motlagh, with whom they acknowledged socializing while Motlagh had liquor license matters pending before the ABC board.

They were also acquitted on a charge under local statutes of conspiring with Motlagh to defraud the city of the "faithful, conscientious" services of public employes.

Both were released on personal recognizance following the conviction, and both face a maximum 20 years in prison. Sentencing is scheduled to occur within the next 45 days.

Barry declined to comment specifically on the case, but said, "This government has a responsibility to present to the public the highest integrity and the highest standards, and those who meet those standards should be in my administration." He said he anticipated no effect on his reelection bid, because "the public knows that Marion Barry himself is honest."

City Administrator Elijah B. Rogers said no decision has been made on whether Lewis and Boardley, both now on leave, will be fired. Rogers noted that both men might appeal the jury's decisions.

On Friday, a second jury that heard the case against Motlagh in the same courtroom convicted the bar owner on the local conspiracy charge of which Lewis and Boardley were acquitted, but acquitted Motlagh of the federal conspiracy charge on which Lewis and Boardley were convicted.

Court officials said it is not unusual for separate juries hearing the same evidence to deliver disparate verdicts. Nor is it unusual, they said, for a single jury to split a verdict on similar charges -- in this case the federal and local conspiracy charges.

All the defendants were acquitted on a federal bribery charge involving an alleged deal among the three of them. Both juries, after hearing numerous secretly taped conversations in which Lewis and Boardley described a "general understanding" with Motlagh that they would receive 3 percent to 5 percent of the store's profits, apparently agreed with the defense that no bribe had taken place.

Boardley and Lewis were convicted of a separate federal bribery charge in connection with their dealings with the Hechinger employe. Defense attorney Watkins contended that Lewis and Boardley could not have sought a bribe from the employe because they offered him nothing in return.

Federal prosecutors declined to comment on the verdict. Jurors, who had been sequestered the length of the trial, were rushed by U.S. marshals to waiting vans and driven home.

Lewis, an architect in the D.C. housing agency before being moved by Barry to head both the ABC and the city's licensing departments, and Boardley, an investigator with the ABC from 1968 until Lewis appointed him staff director, maintained throughout the trial that they were innocent.

Federal prosecutors presented as central to the government's case several secretly taped conversations in which Lewis and Boardley said they had an interest in the liquor store and described the methods they would use to make sure Motlagh would receive a liquor license.

Prosecutors maintained that the tapes proved that Lewis and Boardley had sought, or were expecting to receive, a bribe from Motlagh in return for their help. Lewis and Boardley argued that what the tapes showed were two public officials telling "a whole bunch of lies" on behalf of a friend.

While the officials acknowledged trying to help Motlagh secure a lease at Hechinger Mall, located near the intersection of Benning and Bladensburg roads in Northeast Washington, they said they did so out of friendship, not lust for profits.

Daniel Russell, a Hechinger employe who was in charge of developing the mall, had gone to federal prosecutors in January 1981 saying he believed Boardley had threatened to delay permits for the project if Russell did not award Motlagh a lease.

Russell testified that he agreed to cooperate in a probe of the alleged deal by pretending to want a hidden interest in the store in exchange for granting Motlagh a lease.

Lewis and Boardley maintained, on the other hand, that it was they who were doing the pretending -- that they believed Russell had approached them seeking an interest for himself in the liquor store, and that in order to reassure Russell and help Motlagh get the lease they were pretending to be involved.

The approach they took, they said, was to tell Russell that they had an interest of between 3 percent and 5 percent in the store; that they could guarantee Motlagh a liquor license no matter who protested against it; and that to make sure they were receiving their share, they would have city employes monitor Motlagh's account books. Should Motlagh go back on his word, they assured Russell in the tapes, "we can close his a-- down."

On Jan. 22, Lewis met with Boardley, Russell and "Wade McKeever," an FBI agent posing under an assumed name as Russell's friend and associate in the deal. After touring the indoor pool at Lewis' home in North Portal Estates, the two officials explained their interest in the store, the means they would employ to guarantee Motlagh's license and their own profits and the dangers of the undertaking.

"You know," Lewis told the group, "if this thing goes down wrong, we're looking at jail."

Said Lewis at the trial: "I didn't view that discussion as a meeting. I saw that as a bunch of guys sitting around drinking a whole bunch of liquor and telling a whole bunch of lies."

The government attempted to show that Lewis and Motlagh had been associates for much longer than Lewis was willing to admit, and that Lewis had done numerous favors for Motlagh in connection with the alleged liquor store scheme.

Lewis insisted, despite other testimony, that he had not even met Motlagh until Boardley introduced them sometime in early 1980. He acknowledged occasionally allowing Motlagh to pick up checks when they socialized, but said: "Sometimes he paid, sometimes I paid; sometimes we all chipped in. It just depended on who got to their pockets first, or last."

Boardley, who was responsible for scheduling ABC board hearings, maintained he had no authority to force a liquor store owner to sell his license to Motlagh, as prosecutors contended he did.

Boardley said both his secretary and his deputy staff director were mistaken when they testified that he had given special attention to the liquor license Motlagh eventually bought and that he allowed Motlagh to submit a license application without documents required by the board.

"I didn't know there was necessarily anything illegal," said Boardley, "because we weren't planning to get anything. It was just talk."