Referee may have known his killer, say police Rugby league identity Tony McGrath may have been ambushed by his killer soon after arriving home from a referee training session last week, police say. A friend found Mr McGrath dead in the garage of his Woolloongabba home in Brisbane's inner-south on Thursday night. The 57-year-old, who was recently appointed president of the Brisbane Rugby League Referees' Association, may have been dead for more than two days before his body was found. Tony McGrath died from a single gunshot to the head. He died of a single gunshot wound to his head. Acting Superintendent Brendan Smith said Mr McGrath probably knew his killer, who may have lain in wait beneath his Maynard Street home. "It certainly would appear that it was unexpected," he said. Without going into the details, it's unusual. We believe it to be someone he may know, or had some sort of association with. It certainly appears there has been some sort of confrontation. Neighbours told police Mr McGrath often left his garage door open when he left the house. "When he's home it's shut," Superintendent Smith said. Last Tuesday, Mr McGrath returned home about 8.30pm after attending the training session. Police believe he was killed between 8.30pm and 9.15pm. One neighbour reported hearing raised voices and a loud bang that night. Superintendent Smith said the police investigation was made more difficult because Mr McGrath lived alone and had few close friends. "As he was a bit of a loner, it's very hard to find people that know him," he said. He's got lots of acquaintances, but it doesn't seem like he's got many close friends. Detectives are speaking to members of the referees' association to determine what happened at the Tuesday night training session. "It's certainly a difficult matter," Superintendent Smith said. We're looking down a number of lines of inquiry and we're hoping that one of them will lead to a successful outcome. Mr McGrath never married and didn't have children. The long-time tax office employee, known as "Bunter," dedicated much of the past four decades to the referees' association, where he served as secretary and treasurer. In March this year, he was appointed president of the association, a role Queensland Rugby League south-east division chairman Brad Tallon said Mr McGrath was thrilled to take on. Mr Tallon was at a loss to suggest any motive for the crime. He was always very good-natured. Investigators stepped up their appeal for information on Tuesday morning, as four police divers waded through a 100-metre stretch of Norman Creek at Woolloongabba in an effort to find the gun used in the murder. Detectives are also seeking CCTV from homes and businesses near Mr McGrath's house in Maynard Street. Divers will return to Norman Creek on Wednesday to continue searching for evidence.