A killer has admitted fatally bashing a man in the dark at a unit complex in Canberra's south, apparently under the mistaken impression the victim was a drug dealer.
Grant Allen Q Oldfield, 50, was due to stand trial in the ACT Supreme Court in December, having pleaded not guilty to a charge of murdering Douglas Arthur Creek, 68, in January.
At the time of his committal for trial, Oldfield complained that his case kept "dragging on".
It sped up on Friday morning, when chief Crown prosecutor Anthony Williamson told the court a criminal case conference, conducted the previous day, had resolved the matter.
Oldfield, with his hair pulled back in a ponytail, then stood in the dock and listened as Associate Justice Verity McWilliam's associate arraigned him on the murder charge.
Asked how he now wished to plead, the Kambah maintenance worker looked quickly at solicitor Taden Kelliher before uttering the word "guilty". His voice barely rose above the level of a whisper.
Associate Justice McWilliam subsequently ordered a pre-sentence report at the request of Oldfield's barrister, James Sabharwal, and placed the matter in an administrative list.
Oldfield, who has been behind bars on remand since his arrest on January 23, faces a maximum penalty of life in jail.
Few details of his offending have been aired publicly, and agreed facts outlining the circumstances surrounding the murder are yet to be tendered.
But at the time of the 50-year-old's arrest, Detective Acting Superintendent Callum Hughes told reporters police had been called to a Kambah unit complex about 1.30am on January 22.
He said ACT Policing officers, responding to reports of a disturbance, had found a man with a number of head injuries.
"The man gave an explanation of the cause of his injuries, which did not disclose an offence," the senior detective said.
Paramedics took this man, Mr Creek, to hospital for treatment, but he checked himself out about 12.25pm that day.
"[He] returned to his home and was seen alive by neighbours later that afternoon," Detective Acting Superintendent Hughes said in January.
However, late the following morning, police were told Mr Creek could not be contacted.
Officers went to his home for a welfare check and found him dead inside.
It is understood that in the hours that followed, one of Mr Creek's friends told police the victim had phoned him shortly after leaving hospital and described how he had been "coward punched" and kicked in the head and stomach.
Police are also understood to have spoken to a woman, who told them Oldfield had discussed the incident with her after the fact while bleeding from his knuckles.
She said he had claimed he "didn't know it was Doug", saying he thought he had "bashed" a drug dealer.
Another resident of the unit complex told investigators that before police arrived, she had overheard Oldfield apologising to Mr Creek and saying "I didn't know it was you".
Mr Creek is said to have told Oldfield "it's alright, mate", before telling police he had fallen down some stairs and hit his head.
Oldfield's guilty plea on Friday means his case will now go before the Supreme Court registrar, who will begin the process of setting a sentencing date on September 15.
Having never applied for bail, the killer remains in custody.
