THE man who murdered underworld figure Stephen Cookson and dumped his dismembered body in the ocean off Perth has been sentenced to 23 years in prison.
Aaron Carlino shot 56-year-old Mr Cookson twice in the head with a rifle at point-blank range as he slept on the couch in their East Perth apartment on December 15, 2012.
He dismembered the body with an angle grinder and a knife in the bathroom, then buried the wrapped limbs in the backyard of a Golden Bay property over a period of several hours so the neighbours would not hear.
Carlino retrieved the parts a week later and dumped them a sea.
Mr Cookson's head washed up on a Rottnest Island beach and was discovered by an 11-year-old girl as she beachcombed with her family the following month.
After a three-week Supreme Court trial, it took the jury just a few hours to find Carlino guilty of murder, rejecting his argument he acted in self-defence.
Carlino carried out a "cold-blooded and ruthless execution of Mr Cookson", prosecutor Carmel Barbagallo said in her sentencing submissions on Thursday.
Ms Barbagallo said Carlino's stomach tattoo of the word "Omerta" – the mafia code of silence – and his choice of reading gangster-style books, which Carlino conceded under cross-examination may have inspired him in how to kill Mr Cookson, showed he wasn't of "choir boy" attitude.
She said at the end of their partnership, Carlino was angry and frustrated with Mr Cookson gambling away money that was owed to him, so he killed the older man in order to take over his drug dealing business.
But defence lawyer Laurie Levy said Carlino shot Mr Cookson because he was psychologically damaged and traumatised after months of abuse.
Mr Levy said Carlino was the "antithesis of violence" but genuinely believed that he had to kill Mr Cookson to escape the "defacto prisoner" relationship.
