A former Hyattsville construction supervisor has been convicted in Prince George's County Circuit Court in connection with the fatal shooting of a postman in Beltsville nine years ago.

After 15 hours of deliberation ending Friday, a jury found James Edward Ward, 58, guilty of being an accessory before the fact to the second-degree murder of Gerald Joseph Godbout.

Godbout, the boyfriend of Ward's wife, was shot five times with a .38-caliber revolver on April 28, 1972, as he and Mrs. Ward sat in a car in the parking lot of an apartment complex on Cherry Hill Road.

Ward was arrested shortly after the shooting and brought to trial in February 1975. After one hour of deliberation, a circuit court jury convicted him of arranging with three other men to kill Ward's wife and Godbout.

The conviction was eventually overturned on appeal, and after a long series of legal maneuvers, a second trial began last week, according to Dick Arnold, the assistant state's attorney who prosecuted.

In an unusual twist, the prosecutor at the first trial appeared as a prosecution witness in last week's trial to testify about an incriminating statement Ward had allegedly made to him at an informal encounter long after the trial had ended.

However, Ward's lawyer said another witness testified that he was present at the encounter and that Ward did not make the alleged admission.

Evidence introduced at the trial included a typewritten note describing Mrs. Ward's activities and a typewritten letter once sent by Ward to the county's human relations commission, complaining that the commission was too severe in its dealings with the county police.

The description of Mrs. Ward's activities was seized by police after they stopped a car following the 1 a.m. shooting of Godbout, and an FBI documents examiner testified that there was a reasonable probability that both letters were typed on the same typewriter by the same person.

Ward's lawyer said his client testified that "in effect he did not order the killing of his wife" or ask anyone else to kill her. Two other men previously had pleaded guilty to charges of second-degree murder in the case.

Reports of the earlier trial listed Ward as a member of the conservative Minuteman organization. His lawyer said after the trial, however, that he was aware of no evidence of Ward's membership in the group.

Immediately after the jury brought in its verdict Friday afternoon, Ward, who reportedly had been living in Front Royal, Va., was sentenced by Judge Albert Blackwell to serve a 30-year term, to run from 1975, the year of the original conviction.

Ward's lawyer said he would appeal.