Blood had been smeared across walls, in his kitchen and on his armchair. Furniture was upturned and rubbish scattered across the floor.
Almost three years later and despite police and coronial investigations, the identity of the person who injured Mr Williamson remains a mystery, the Coroners Court of Victoria was told on Tuesday.
The 54-year-old died at Alfred hospital on July 11, 2020, about two weeks after police found him injured inside his apartment in Gippsland, southeast Victoria.
"The precise circumstances in which James Bernard Williamson suffered his injuries are unknown," State Coroner John Cain said.
"However, it is likely the injuries were sustained as a result of the actions of a person or persons unknown."
Mr Williamson died from multiple injuries to his brain, face and ribs, and due to complications from diabetes, heart and lung disease, Judge Cain said.
Homicide detectives had investigated the circumstances of his death, speaking to witnesses, door-knocking neighbours and searching through his phone and bank records.
Investigators discovered that at 8.14am on June 27, the morning before police found him injured in his Morwell apartment, a call was made from Mr Williamson's phone to Morwell Taxis.
A man gave the taxi company the name Wayne and was picked up from Princes Drive in Morwell, near Mr Williamson's apartment, and driven to an address in Churchill.
The taxi driver told police the man he picked up claimed Mr Williamson "had been bashed", but he did not know how or who was involved, Judge Cain said.
He said police later found Mr Williamson's sim card inside the iPhone of an associate named Brenton Boyd.
Mr Boyd admitted he had used methamphetamine and heroin with Mr Williamson on June 26, and said he heard "rumours" that people believed he had assaulted him, although he denied this occurred, Judge Cain said.
In early 2020, the pair were caught on police body-worn camera footage arguing when Mr Boyd was arrested for possessing heroin.
"He's angry at Mr Williamson at the time of arrest. Several members of the public had alluded to this fact," Judge Cain said.
However, DNA evidence was unable to link him to Mr Williamson's injuries. Mr Boyd was charged with offences relating to the stolen sim card.
"Despite a thorough investigation, no person or persons have been charged with an indictable offence in connection with Mr Williamson's death," Judge Cain said.
The Coroners Court may reopen its investigation and set aside the findings if any new facts or circumstances arise in the future.