An ice user "let a rabid dog off the leash" in rural Victoria the night he orchestrated the fatal home invasion of a sleeping elderly man.
Adam Lucas Williamson, 40, was the "driving force" behind the deadly burglary at the Springbank home of Kenneth Handford in September 2015.
Williamson had earlier met Mr Handford when they worked together at a potato farm, and harboured a grudge against the elderly man when accused of stealing money from him.
Williamson, a drug addict, needed money to fund his ice habit.
He knew the 89-year-old would be in possession of a large sum of money, because of the veteran's habit of not using banks.
The ice smoker falsely told his associate, sex abuse victim and fellow drug user Jonathan Jeffrey Cooper, that Mr Handford was a pedophile.
Cooper organised a double-edged knife for the burglary.
The pair broke into the elderly man's cottage in the early hours of September 14, 2015.
The veteran woke and Cooper shone his torch in the man's face before striking him with it.
Mr Handford was hogtied and a gag forced into his mouth before Cooper stabbed him 13 times, accusing the innocent man of being a pedophile.
"He ultimately stabbed the deceased repeatedly in the back while he was tied up and unable to defend himself," Supreme Court of Victoria Justice Jane Dixon said to Williamson.
"You are therefore criminally responsible even though you did not inflict the stab wounds to Mr Handford.
"Your conduct was brutal and cowardly".
The pair stole Mr Handford's war medals.
The grandfather's body was found the next day, on what would have been his 90th birthday.
Speaking outside court, Mr Handford's granddaughter Leah said the family felt Williamson's 27-year jail sentence was appropriate following the death of her beloved "larrikin" grandfather.
"As far as I'm concerned, Williamson let a rabid dog off the leash that night. They are both responsible," she told reporters.
"The fact that this fight is over means one thing for us. We don't have to live like this anymore and we'll have an opportunity to properly grieve a much-loved man."
Williamson must serve 23 years in jail before he is eligible for parole.
Cooper was jailed in 2017 for 16 years, which has since been increased to 24 years on appeal.