WA police baffled by Swanbourne homicide WEST Australian police say they're baffled by the shooting death of a man whose family described as a harmless person who had worked and lived for the surf. David Liam Johnson, 32, was found dead at the weekend with a gunshot wound to his head at a park in the Perth beachside suburb of Swanbourne. Police, who are treating the death as a murder, said on Thursday they had ruled out the involvement of bikies, but were at a loss in finding a motive for the shooting. Mr Johnson was known in the Mandurah and Fremantle areas, but had no fixed address. Commissioner Karl O'Callaghan told Fairfax radio on Thursday that the case remained a mystery. "The only thing I can tell you is that in the briefing note I've got ... it's not related to bikie activity," Mr O'Callagan said. Mr Johnson's family have pleaded for anyone with information about his death to contact police, saying he was a free spirit who worked to support his love of surfing and would never have hurt anybody. "And that's why I think it doesn't make any sense from a motive perspective - I think we're still fairly baffled about it," Mr O'Callaghan said.