Brent Donald Mack, 27, murdered his mother Ah Bee Mack (also known as Pauline), sometime in late December 2008. Ah Bee was last seen alive at a family function in September 2008. Her brother and sister-in-law had grown concerned when they had not heard from her for over a year and started receiving odd messages from her son Brent.

When Ah Bee’s second son, Adrian started asking questions about his mothers whereabouts between September 2010 and February 2011 Brent told him she was a “psycho who was being looked after by a man”, living near Dianella (a Perth suburb).

In 2010 Ah Bee was reported missing by her sister-in-law after she had received a card she believed was suspicious as the handwriting on the card was not Ah Bees and it had been signed in a name she never used.

Brent was arrested and charged with Ah Bee’s murder. The prosecution argued that Brent killed his mother for money and property she inherited after his father’s death in August 2008. Brent was alleged to have forged his mother’s signature after her death and taken over $200,000 from her bank accounts.

Brent pleaded not guilty to the murder, claiming his mother committed suicide in their Mount Hawthorn home and he disposed of her body, her remains have never been found.

Brent was sentenced to life in prison the Court observed his behaviour pretending that his mother was still alive if she had killed herself, was “inexplicable and incredible”, concluding his story of suicide was “yet another lie”.

Under the forfeiture rule a person “should not slay his benefactor and thereby take his bounty”; therefore a person convicted of unlawfully killing is not allowed to benefit from the death of their victim. The doctrine includes manslaughter. Brent’s conviction automatically prohibited him from benefiting from his mother’s estate.

In July 2014 Brent’s brother Adrian died intestate. In October 2016 a grant of letters of administration to the Public Trustee (“the Administrator”) of Adrian’s intestate estate was made. Brent and Adrian’s half brother Gary (who is not a child of Ah Bee Mack) are entitled to be beneficiaries of the estate under the Administration Act.

The administrator sought the Supreme Court of Western Australia’s direction as to the distribution of that part of Adrian’s estate incorporating Ah Bee’s estate. As Australian law is unclear about whether Brent could benefit from Adrian’s estate – and therefore indirectly Ah Bee’s, – the Court was provided with no evidence to suggest any significant modification to Adrian’s estate since he inherited his mothers estate, and tellingly it included the family home where Ah Bee was murdered.

The Court was asked whether the administrator should divide Adrian’s estate evenly between his two brothers, or whether Brent had forfeited his right to a benefit by killing his mother. The Court held Brent was not entitled to any of his brother’s estate derived from his mother’s, but could be a benefactor for any assets Adrian gained that were unrelated to his mother’s death.

The Court held the logical extension of the rule of forfeiture that a convicted murderer could not benefit directly or indirectly as a consequence of his crime should apply. Although Brent was not responsible for Adrian’s death, his estate, would not have acquired any interest in Ah Bee’s estate but for her death. Furthermore, Adrian would not have had an entitlement to the whole of Ah Bee’s estate but for the forfeiture rule applying owing to her death at Brent’s hand.

As there was no Australian example of this series of events, the Court found that several persuasive American decisions which supported the proposition that a person should not benefit directly or indirectly as a consequence of a crime for which they have been convicted. The Court directed the administrator to ensure Brent does not gain a benefit following from his criminal conduct.