Hayden Leigh Kidd: Young man killed grandmother Shirley Kidd with mattock in drug-induced psychosis

A young man bludgeoned his own grandmother due to the deluded belief she was his abusive stepfather, a court has been told.

Hayden Leigh Kidd, 22, appeared in the Supreme Court of Victoria on Tuesday after pleading guilty to manslaughter over the death of Shirley Kidd, 67, two years ago.

Kidd’s murder trial was aborted in April after prosecutors accepted an 11th-hour offer to plead to manslaughter.

Crown prosecutor David Glynn said Mrs Kidd was found dead in the garage of her Darley home, about 60km northwest of Melbourne, on May 28, 2022, by her husband, Robin, after he was woken by their seven-year-old grandchild.

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“Hayden did it, he hurt mama,” the young boy said.

Kidd kept his eyes closed as details of the horrific offending were read to the court and three members of his extended family delivered victim impact statements.

Mr Glynn said Mrs Kidd was found with a mattock axe in the back of her head, with an autopsy finding injuries consistent with her being struck “at least” four times.

He said Kidd was confused when emergency services approached and was found to have trace amounts of cannabis in his system.

Kidd’s barrister, Tim March, told the court that two forensic psychiatrists found his client was experiencing transient drug-induced psychosis, “mistaking” his grandmother for his abusive stepfather in a confused delusion.

“This is a serious and savage homicide, shockingly so,” he said.

“There is no rational explanation… but for this bizarre confluence of psychosis and PTSD.”

Mr Marsh argued the attack would not have occurred but for Kidd’s psychosis and PTSD from years of sadistic torture at the hands of his stepfather.

He said Kidd’s mother had detailed the incredibly confronting nature of Kidd’s abuse from the age of two to his teenage years when they fled.

“Shirley and Robin Kidd provided the only sanctuary, the only respite that Hayden ever knew as a child,” Mr Marsh said.

Shirley Kidd (left) was killed by her grandson. Facebook/Supplied Credit: Supplied

He said his client had detailed smoking a small amount of cannabis and going to bed feeling ill before waking later that night.

On his account, Kidd entered his grandmother’s bedroom and immediately snatched his cousin, believing he was a younger aspect of himself and his grandmother was his stepfather.

Mr Marsh said his client fled through the house into the garage and remembers swinging an object at his pursuer.

Mr Marsh said but for his client’s drug use, he would likely have had a mental impairment defence for causing the death.

He called on Justice Michael Croucher to issue a sentence permitting Kidd to rejoin the community under supervision “as soon as possible”.

Mr Glynn, on the other hand, argued Kidd’s offending required imprisonment “of an appropriate length”.

Shirley Kidd was remembered as the heart of a large extended family and always “happy and positive”.

Her son, Matthew, said he was robbed of the chance to prove to his mum that he had turned his life around.

“I will never forgive myself… I will live the rest of my life being the man you hoped I would be,” he said.

Justice Croucher adjourned sentencing until August 1.