John Spencer White, 63, admitted the 2001 manslaughter of John Christianos, whose remains were discovered at Oakleigh South last year.

White was on Thursday jailed for a maximum six-and-a-half years for killing the artist he had hired to paint portraits for his sporting collectables store, Memorabilia Headquarters.

White also gave Mr Christianos a place to live as he battled alcohol and mental health issues.

Justice James Elliott said the pair met in 1999 and were friends until things started to unravel.

Mr Christianos had attacked White, threatened him and on occasion brandished a knife in “intimidating and frightening” incidents.

He said there were signs before Mr Christianos’s death that his life was spiralling out of control.

On June 11, 2001, Mr Christianos threatened his friend with a knife, White told police after his arrest last August.

He said he was “petrified” and acted in self-defence, shooting Mr Christianos twice with a WWII handgun he’d bought to protect himself.

He panicked, stuffed the body headfirst into a bin and took it to a storage facility where he kept memorabilia.

White lied that Mr Christianos was suicidal, but his body was discovered after the storage fees ceased.

White stopped paying the storage fees in 2004, but Mr Christianos’s body wasn’t found until July 2018 when workers cleaning out the locker made the “gruesome” discovery.

Justice Elliott said White wrote to the court to express his regret and remorse for the killing, its effect on the dead man’s family and those who found his body.

The judge found White was otherwise outstanding in making the most of limited opportunities available to him in his early years, and had lived a life caring for others.

“It is completely irrefutable your killing of Mr Christianos was completely out of character,” he said, though acknowledged obtaining and using the gun had been a conscious, unlawful decision.

White has already served 10 months in prison.