Campsie double stabbing: Marvin Mahoney refused bail on attempted murder charges

A man accused of repeatedly stabbing two family members in a frenzied attack allegedly told police he had every intention of murdering the couple, a court has heard.

Marvin Mahoney, 25, was refused bail by the NSW Supreme Court last month on attempted murder charges.

A man accused of repeatedly stabbing two family members in a frenzied attack inside a Campsie home allegedly told police he had every intention of murdering the couple, a court has heard.

It comes as police allege a family dispute over inheritance money sparked the chilling confrontation, which saw 25-year-old Marvin Mahoney arrested and left his 46-year-old cousin fighting for life in hospital.

Police allege Mahoney, who suffers from a range of mental illnesses, used a fishing knife to stab his cousin and his cousin’s partner as they lay in bed on the evening of April 10.

According to police, the relationship between the two men had soured in recent years following the death of Mahoney’s father in 2022.

Documents tendered to the NSW Supreme Court said Mahoney’s father left him money from his estate, but disputes over the cash, along with a series of criminal allegations levelled at Mahoney’s father before he died, had driven a wedge between the cousins.

Police and forensics pictured outside the Campsie home where the stabbings allegedly occurred. Picture: NCA NewsWire / Damian Shaw

Following an argument between the pair on the phone on April 7, Mahoney allegedly told his mental health case officer that he wanted to kill his cousin, prompting the worker to alert police.

However, it is alleged Mahoney moved to enact his plan just days later, allegedly arming himself with a fishing knife on the evening April 10 and leaving his home to walk to his cousin’s house.

Court documents state Mahoney found both victims lying in bed and allegedly started “slashing and stabbing” the pair with his knife.

“During the attack, [Mahoney’s cousin] has lost consciousness, suffering multiple stab wounds to the torso, arms, hands, face and neck,” court documents state.

“[His partner] suffered wounds to the head, arms, hands and legs. During the attack [she] was screaming for help and as a result, a neighbour has contacted police.”

It is alleged Mahoney ran from the home, discarding his bloodstained t-shirt at a nearby unit block.

Meanwhile, emergency services arrived within 15 minutes and began working on Mahoney’s cousin, who was in a critical condition and required six bags worth of blood before being transported to hospital for urgent surgery.

Mahoney was arrested a short time later and taken to hospital for treatment.

A forensic examination of the scene was carried out. Picture: NCA NewsWire / Damian Shaw

When interviewed by detectives the following day, Mahoney outlined the background to his dispute with his cousin and allegedly admitted he had gone to his home the previous night intending to kill him.

“From the moment I left my house, I had the intent to murder them,” he allegedly said.

“I just went for ‘em, I went slashing, slashing, slashing, hitting, hitting as many times as I could, I was trying to fight ‘em both at once and I just ended up getting tired and leaving.”

Mahoney was charged with two counts of attempted murder and remanded in custody at the time but made a bid for bail in the Supreme Court last month, with his legal team saying it was likely he would argue a mental health defence against the charges.

The court heard he was currently being housed in the prison hospital at Long Bay but wanted to attend Connect Global, a drug and alcohol rehabilitation centre near Port Stephens.

In refusing the application, Justice Sarah McNaughton rejected claims that Mahoney did not present an unacceptable risk to the safety of others if released.

“In my view, the prospect of Connect Global being able to supervise this seriously unwell person to make sure that he takes his medication and that no other resident of the rehabilitation centre is not put in danger … is, quite frankly, not able to be accepted by the court,“ she said.

The case will return to court early next year.