Calls from witnesses have led South Australian police to the scene of an assault which resulted in the death of missing NSW man Peter Hillier.
Mr Hillier's body was found in a holiday house at Venus Bay on Eyre Peninsula on Monday.
But police believe he was assaulted earlier behind the art gallery at Poochera about 60 kilometres northwest of Streaky Bay.
The 64-year-old's travelling companion, a 43-year-old man also from NSW, has been charged with his murder and is being held in custody.
Detective Superintendent Des Bray said calls from the public had led police to the Poochera location where they found a possible murder weapon.
"We have recovered crucial evidence at the scene which makes it clear to us there was a very significant assault," he said.
"We recovered items from the scene that we can directly connect to the victim."
Supt Bray said it was believed Mr Hillier and the accused had gone to Poochera to socialise with other people and it was likely the pair were drunk at the time of the assault.
Police believe they have a motive for the attack but have declined to provide details.
It remains unclear if Mr Hillier, who was reported missing last week, died at Poochera, at Venus Bay, or at another location.
It was believed he left NSW with his accused killer about a month ago.
The pair were travelling in a motorhome Mr Hillier had recently purchased.
On Monday, a call to the ambulance service indicated he had been injured after falling from a vehicle while drunk on the way back from a fishing trip.
But when crews arrived at the Venus Bay property he was already dead.
Det Supt Bray said subsequent investigations led police to believe Mr Hillier had not been injured in a fall but had been killed.
"His injuries are significant and we don't believe it's consistent with falling from a vehicle," Det Supt Bray said.
"He had been dead for a period of time."