A 43-year-old man from the New South Wales Central Coast has been charged with the murder of a 64-year-old man at South Australia's Eyre Peninsula overnight.
South Australian Police allege Peter Hillier was murdered by his travel partner near Venus Bay while the pair were road tripping around Australia.
Police say the offender made the initial call to emergency services about 11am on Monday, stating that Hillier had fallen off a motor home.
SA Superintendent Des Bray said the "significant injuries to his body" were not consistent with that of an accident.
"We're happy that we can establish that Peter was the victim of a murder as opposed to an accident," Bray said.
Hillier was reported missing from NSW on May 25 this year.
His last known location interstate was Lake Haven in NSW.
SA Police established a crime scene at a holiday home on Sandham Street where the body was found.
"The motive for the murder is not clear at this stage," Bray said.
"Nor is the location of the death."
Police are urging anyone who may have seen the "very very distinctive" Mercedes motorhome the pair were travelling in to call Crime Stoppers.