A Mt Hawthorn man who murdered his mother for financial gain has been sentenced to life in prison.
Brent Donald Mack, 28, will not be eligible for release on parole until 2030 after he was found guilty of murdering his mother Ah Bee "Pauline", who disappeared in December 2008.
Her body has never been found.
Mack, who is autistic, stood in the dock with his eyes closed and head bowed as the sentence was delivered.
Sentencing Mack to a life sentence with a non-parole period of 20 years, Supreme Court Justice John McKechnie said his autism did not "explain (his) crime, let alone excuse it".
Justice McKechnie said he did not find any causal link between Mack's autism and him murdering Mrs Mack.
He said Mack, who had a lengthy criminal record of dishonesty offences, was a "dishonest devious individual" who lied to cover up his mother's murder.
He accepted Mack would face a difficult time in prison because of his autism.
Defence lawyer Seamus Rafferty said Mack, who had a difficult childhood marked by loneliness, loved his mother and had been close to her.
In November, Justice McKechnie found Mack murdered his mother sometime in December 2009 to access her bank accounts and property.
He said Mack went to elaborate lengths, including forging his mother's signature and fabricating a greeting card, to convince friends and relatives she was still alive.
Justice McKechnie said Mack would receive psychiatric services in prison but whether he used them was another matter.