Killer sentenced over death of Adrian Trett, the man found abandoned on a Mannum footpath

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A Mannum man will spend almost four and a half years in prison over the death of Adrian Trett, who never woke up from a coma after being found on a footpath in 2018.

Fifty-one-year-old Glen Kerry Patterson was sentenced for his “selfish and inexcusable” actions in Adelaide’s District Court on Thursday.

Patterson and Mr Trett were friends who had been consuming alcohol and cannabis during the evening leading up to Mr Trett’s death, Judge Ian Press recounted.

In the early hours of the morning, as Mr Trett was leaving Patterson’s house at Mannum, the pair got into an argument about whose turn it was to buy methamphetamines.

Patterson punched Mr Trett in the back of the head without warning, knocking him down a flight of stairs and causing injuries from which he would die two weeks later.

“He was not in a state to defend himself,” Judge Press said.

“A reasonable person would have realised you were exposing him to ... an appreciable risk of serious injury.”

The offender and another man then wrapped Mr Trett in blankets and put him in a gopher, to take him to hospital.

But they panicked on the way and dumped him on a footpath on David Street.

Patterson had consciously chosen to put his own self-interest ahead of Mr Trett’s health, Judge Press said – and that made the offending worse.

“The community is entitled to expect that even those who have done wrong will not act with callous disregard for the wellbeing of their victims,” the judge said.

Patterson later lied to police about his involvement and even attended Mr Trett’s funeral, a fact which later filled the victim’s family with even more grief and anger.

The offender’s prior history of violence was revealed in court: he had been convicted of assault six times since 2001, and been to jail twice.

Patterson also had problems with drug abuse, anger management and impulse control, Judge Press said.

But he had sobered up while in police custody and wound up pleading guilty to the charge of manslaughter.

“Mr Trett was your friend, and ... the enormity of what you have done has slowly but gradually become very real for you,” Judge Press said.

Patterson’s final sentence was reduced by 30 per cent thanks to his early guilty plea, and set at five years, six months and 25 days.

He will become eligible for parole in 2024.