A 10-year veteran of the D.C. police force was convicted yesterday of being an accessory after the fact to an assault for trying to cover up the involvement of another man in a 1980 murder.

James R. Shaw, who was suspended from his post as an officer in the 7th Police District shortly after the incident, faces a maximum sentence of six months in prison.

A second man, Antone D. Ruffin, 25, was convicted of second-degree murder and mayhem in connection with the incident, in which 33-year-old Clifford Wilson was beaten. Wilson later died.

According to court testimony, Shaw had been the boyfriend of Ruffin's sister. Both men acknowledged in court that they went to the woman's apartment on Feb. 3, 1980, after family members reported that Wilson, a longtime friend of the Ruffin family, had tried to rape her.

Wilson suffered a skull fracture and massive swelling of the brain after being beaten that night. He never regained consciousness and died at George Washington University Hospital five months later.

Ruffin acknowledged during the trial that he had kicked Wilson, but said it was in self-defense and said he later saw Shaw beating Wilson with his police revolver. Shaw said he found Wilson lying unconscious in the building with Ruffin and several friends and family members standing over him. He denied telling police he had beaten Wilson while trying to arrest him on a charge of attempted rape, as five officers testified.

Witnesses to the incident said Shaw told them not to speak to police about Ruffin's involvement and that he would claim responsibility for striking Wilson while trying to arrest him for attempted rape.