After his roommate died in an early-morning struggle over a rifle, Joseph Patrick Larkin went to great lengths to conceal what occurred, according to testimony yesterday at his homicide trial.

Prosecution witnesses said he ripped up the carpeting in their Pennsbury Village townhouse, duct-taped the bullet hole in Chad Mulvin's chest, stashed and buried his body, tossed the .22-caliber weapon in the Ohio River and made several calls to Chad Mulvin's friends and family to ask if they knew where he was.

The two men, who were close when they moved in together, had spent the evening of July 1, 2004, at Jabby Joe's bar, at a luau-themed goodbye party for one of Mr. Mulvin's co-workers from the Red Lobster in Robinson, witnesses said. Several hours into the party, Mr. Mulvin, 29, became visibly upset when he realized Mr. Larkin, then 31, had stuck him with their $68 bar tab and left him stranded without a ride home.

Ten days later, Mr. Larkin told Allegheny County homicide detectives that Mr. Mulvin came home early July 2 and grabbed for his roommate's rifle. He told police the gun went off when he tried to block Mr. Mulvin from putting his finger on the trigger.

Shortly after Mr. Mulvin disappeared, investigators spoke with one of his co-workers who rode in the car pool that ultimately took him home from Jabby Joe's. In that interview, William "Tank" White said Mr. Mulvin became increasingly irate as he called Mr. Larkin from the bar -- a total of 22 times, records would later show. Mr. White told police he overheard his co-worker say he was going to go home and give Mr. Larkin a "beating." But Mr. White testified yesterday that he did not recall hearing the outburst.

Testimony in the nonjury trial before Allegheny County Common Pleas Judge Kevin G. Sasinoski will resume today.