A man who murdered his father in a bid to collect an insurance payout has been sentenced to 37 years' jail.
Michael Martin senior died after being stabbed 16 times with a samurai sword in a house at Murwillumbah in 2014.
His son was found tied up at the scene, but a jury found him guilty of murder after a lengthy trial last year.
Three life insurance policies taken out on Michael Martin senior by his son in the months leading up to the killing were a key piece of evidence.
The Supreme Court heard the policies were worth a total of $2.5 million.
The killer made a botched attempt to murder his father in April of 2014, but the brutal attack left the victim blind in one eye and suffering life-threatening injuries.
The court heard Michael Martin junior visited his father in hospital and witnessed the harm he had caused, yet went ahead with his deadly plans just two months later.
Judge Peter Hamill likened the attack to a cold-blooded contract killing.
"The offence was committed for financial gain," he said.
"It involved a brutal attack on a vulnerable man in the victim's own home.
"The offence was carried out with a cold-blooded determination scarcely imaginable to ordinary members of the community guided by moral and ethical standards inherent in most human beings."
The defence had argued it was a crime of revenge and retribution sparked by a childhood of neglect and deprivation.
But Justice Hamill said while there was evidence of abuse, violence and neglect, he could not accept that the 28-year-old killer acted out of provocation.
He imposed a total sentence of 37 years in jail, with a non-parole period of 27 years and nine months.
The killer sat rigid and expressionless as the sentence was read out.
Last year his ex-wife, Candace Martin, pleaded guilty to attempted murder and being an accessory after murder.
She was given a sentence of nine years' jail with a non-parole period of four years.