A Charles County, Md., jury has convicted a District of Columbia police officer of being an accessory in a tangled slaying in which the body of a fellow officer's wife was found in a shallow grave outside Waldorf, Md.

Officer Harry Jennings, who has been suspended since he was arrested last fall, was acquitted of first- and second-degree murder charges and conspiracy after a four-day trial at which his colleague, Officer Steven John Shalkowski, testified against him.

Last April, Shalkowski was sentenced to 20 years after he pleaded guilty to second-degree murder in the death of his 26-year-old wife, Irene. Shalkowski, an eight-year veteran of the District police force, had first told authorities his wife was missing on Oct. 28, 1979. He was arrested six weeks later in December after his wife's body was found stabbed and shot in the woods outside Waldorf.

Jennings, who lives in Waldorf, 25 miles south of the Shalkowski's home in Takoma Park, originally had been charged as only an accessory after the fact for his role in allegedly helping to bury Irene Shalkowski's body in his neighborhood.

But Jennings was reindicted last May after Shalowski pleaded guilty and agreed to testify against him, a former friend and an officer whom he'd once worked with at the District's 7th Police District.

At the trial, in Charles County Circuit Court Shalowski testified that he had choked Irene Shalkowski until she was unconscious but said that it was Jennings who stabbed her four times with an icepick and fired two shotgun blasts into her chest.

Jennings pleaded innocent to all charges, claiming that Shalkowski had dropped by with his girlfriend on Sunday, Oct. 20, the day before Irene was killed. He said that he hadn't seen Shalkowski again until two weeks later at the police department's pistol range when, his lawyer said, Shalkowski tried to sell him Irene's sewing machine.

At the trial, Shalkowski testified that he had become infuriated when his wife danced too closely to men at a police retirement dinner and he admitted that he had struck her, tearing out an earring.

Jennings is free on bail pending his sentencing September 25.