Human remains found at park in a small South Australian town last month have been identified as missing man Ian Lees, police say.
His remains were found by a bushwalker in the Hale Conservation Park at Williamstown, 50 kilometres north-east of Adelaide, in late July.
The 53-year-old was reported missing on March 4.
Detective Inspector Brett Featherby said it was evident Mr Lees had suffered "significant physical injuries" and his disappearance has been declared a major crime, with police suspecting he was murdered.
Detective Inspector Featherby said Mr Lees left his Modbury North home around 6:30pm on February 28 and was last seen in the early hours of March 1 walking on Fairleigh Avenue.
Council workers found his phone at Civic Park, opposite Tea Tree Plaza, later that day and police found his backpack in bushes on Fairleigh Avenue about a week later.
He said Mr Lees frequented the Modbury North and Tea Tree Gully area with his blue heeler named "Jasper".
Detective Inspector Featherby described Mr Lees as a "very social person" with a "large friendship group".
"He had a keen interest and knowledge in football at all levels and enjoyed debating statistics on that topic," he said.
Detective Inspector Featherby said the criminal investigation was in its infancy and police were "keeping an extremely open mind in relation to what the motive may be".
"By all accounts Ian was a very jovial person and he did have that social group so we just don't know what the motive is at this stage and that's why we're seeking public support," he said.
Detective Inspector Featherby said Mr Lees had not accessed any of his bank accounts and police were currently searching his home.
Detective Inspector Featherby said Mr Lees was found 50 metres from a fire track at the Hale Conservation Park at Williamstown and it was near a public car park.
"We don't exactly know if ... he has been murdered elsewhere and placed at the location he was found by the bushwalker," he said.
He said Mr Lees had been in the conservation park "for months" and police believe he was murdered shortly after going missing.
In April, police and Mr Lees' family appealed to the public for help in finding the missing man.
At the time, Mr Lees' niece Grace said her family was "missing our uncle greatly and struggling with the unknown of the situation".
"He is a lovely man, and we are very concerned," she said.
Detective Inspector Featherby said it was "extremely difficult" to have a family member reported missing.
"Unfortunately, in this circumstance, their loved one hasn't returned home, and they've had to be informed that it's suspected he's been murdered," he said.
"I can't put myself in their place, but I can only imagine how heartbreaking it would be because he did have good family support."
Police have called for information from members of the public who visited the park, or may have dash cam vision from that area, between March 1 and 7.