A jury in federal court yesterday convicted bar owner Tommy M. Motlagh of conspiracy in connection with an alleged deal to share profits from a liquor store with city licensing officials in exchange for their guarantee he would receive a license to operate.

Motlagh, who allegedly agreed to give a hidden interest in a proposed liquor store at Hechinger Mall to the former chairman of the D.C. Alcoholic Beverage Control Board and the board's staff director, was convicted of a single conspiracy count under local statutes.

A District Court jury of eight women and four men, who had heard the case for two weeks, acquitted Motlagh of two more serious federal charges of conspiring to bribe Robert C. Lewis, former ABC chairman, and James E. Boardley, Lewis' top aide.

The local felony charge--conspiring to defraud the city of "faithful, conscientious" services of public officials--carries a maximum penalty of five years in prison.

Motlagh, an Iranian national and owner of the Bastille nightclub in College Park, remained free on personal recognizance but was ordered to surrender his passport. He is scheduled to be sentenced within the next 45 days.

A second jury considering charges against Lewis and Boardley was still sequestered at a hotel at 8:15 p.m. after it failed to reach a verdict.

For the first time here, two juries were empaneled to hear the cases separately, but in the same courtroom.

Jacob Stein, Motlagh's attorney, said he was "obviously pleased" that his client was acquitted on the more serious federal charges.

Government prosecutors declined to comment on the verdict. The Motlagh jurors dispersed quickly, declining to discuss their deliberations.

Assistant U.S. Attorney Richard Beizer, making final arguments for the prosecution yesterday, said Lewis and Boardley "had their arms in the cookie jar all the way up to their shoulders" and were caught with "crumbs all over their faces."

Stein said in his closing argument that all three defendants had been trapped, and that the government's case had "too many props."

Because two juries had been empaneled in the case--one for Lewis and Boardley and the other for Motlagh--Beizer summarized the government's evidence separately to each jury.

Lewis, Boardley and Motlagh all sat expressionless around the defense table as Beizer accused them of offering a phony explanation for statements they made in secretly recorded conversations with Hechinger employe Daniel Russell, who cooperated in a federal probe of the alleged deal.

Stein said the government's case failed to document any meetings among the three defendants and that Russell "wanted to trap Boardley, Lewis and Motlagh."

Before he was dismissed from his city post last year, Lewis had been head of Licensing, Investigations and Inspections, a cabinet-level job. He was appointed by Mayor Marion Barry, whose campaign for mayor Lewis supported.

In 1979, Lewis named Boardley, a former ABC investigator, the board's staff director. Boardley also was dismissed from that post.

Both acknowledged on the witness stand trying to help Motlagh in his efforts to aquire a lease for a liquor store in the mall at Bladensburg and Benning roads NE. They denied, however, that their assistance was based on an agreement with Motlagh that they would have a hidden interest in the store's future profits.

The government's case hinged on a series of conversations taped in January and February last year. In those tapes, jurors heard Lewis and Boardley describe a "general understanding" with Motlagh that they would receive between 3 percent and 5 percent of the store's future profits. In return, they would guarantee that Motlagh received a liquor license to operate the store, no matter what opposition to the license might arise.

Lewis and Boardley never disputed their words on the tapes. Instead, they insisted that the things they told Russell were all lies calculated to convince him that they, too, were involved, and that Motlagh therefore could be trusted to share his profits once Russell approved the lease.

They could not possibly have meant what they said, the officials maintained, because they were restricted in their actions by the same laws and regulations they were accused of breaking.