Funeral services will be held for a Massachusetts firefighter who was allegedly shot by a friend while the two were drinking and playing with a handgun.

David Atherton will be laid to rest on Thursday in Lindenwood Cemetery in Stoneham following a funeral Mass at St. Patrick's Church.

Police have said that Atherton's friend, Patrick Riccardi-O'Connor, has admitted to shooting Atherton on June 28 while they were "fooling around with the gun." Riccardi-O'Connor has told police that he didn't think the gun was loaded. He has pleaded not guilty to charges of involuntary manslaughter and related crimes.

Both the 24-year-old Atherton and the 23-year-old Riccardi-O'Connor were military police officers in the Massachusetts Army National Guard. The gun was registered to Riccardi-O'Connor. The two men had been friends since childhood.