A BASE jumper who plunged to his death from Australia's tallest structure may have been wearing a helmet camera, which could hold clues to what happened.
Fairfax Media believes Ash Cosgriff, a 23-year-old skydiver and BASE jumper, plummeted to the ground near the Omega tower, a 432-metre navigation antenna and transmitter, at Giffard, about 200 kilometres east of Melbourne, on Saturday afternoon.
Police believed a helmet was removed from Cosgriff's body before emergency services arrived.
A mount for a camera was attached to the helmet, but no camera was found.
Ambulance Victoria spokesman John Mullens said ground crews and a helicopter were dispatched but the man was difficult to access.
''It came through as a base jump man in his 20s believed to be deceased,'' he said.
Emergency services workers had to be directed to the site by people who had been with the man, Mullens said.
''It took a little while to get in,'' he said. ''He was deceased.''
Police said it was most likely a parachute malfunction that caused Cosgriff's death and that they were searching for another man they believed was with Cosgriff when he died.
''We are concerned someone removed his helmet from the body, which had a mount for the camera,'' Detective Sergeant Ian Marr said.
''The person who left the scene is most likely the friend of the person who has been killed.
"I suspect he may have been spooked and run off. But he really needs to come and speak to us.''
Cosgriff, a member of the Newcastle Sports Parachute Club, was a skydiver who also did BASE jumping on the side.
BASE is an acronym for building, antenna, span (bridge) and earth (cliffs) - the four places from which jumpers launch.
The drop zone safety officer at the Newcastle Sports Parachute Club, Michael McGrath, said Cosgriff held a D-licence in skydiving and had made more than 200 skydives.
McGrath said it was important to differentiate between skydiving - an activity that is regulated by the Civil Aviation Safety Authority - and BASE jumping, an illegal and unregulated parachute jump from a fixed point, usually from a tall building or promontory rather than an aircraft.
In skydiving, a person carries a reserve parachute, McGrath said.
In the case of BASE jumping, a person has the use of only one parachute, which is usually opened very close to the ground.
''From what we hear, Ash deployed his parachute marginally too late and, before it had time to completely open, he impacted the ground,'' McGrath said.
He said Cosgriff's tragic fall would not deter other BASE jumpers, because ''BASE jumping is a high-risk sport and people who do it know the risk''.
- Sydney Morning Herald