Man jailed for murdering Melbourne nurse he thought was the devil

WARNING – DISTRESSING CONTENT: Two days before Melbourne nurse Caitlin O'Brien was killed by her boyfriend she told him she feared it would happen.

He'd been violent towards her for most of their more than decade-long relationship and the abuse became fatal in the middle of a cannabis-induced psychotic episode last June.

Shea Dylan Sturt was on Wednesday jailed for 22 years. Ms O'Brien's family hope he spends those years getting the help he needs.

Martine O'Brien says her family lost two people the day her 31-year-old sister died.

"I just hope that he uses the next few years to rehabilitate himself. That's what my sister would have wanted," she said after a judge ordered he spend at least 16 years in prison.

Melbourne nurse Caitlin O'Brien's partner who killed her has been jailed for 22 years. Source: Facebook

Sturt, now 33, was having delusions when he killed Ms O'Brien, who was recovering from brain surgery.

He believed she was the devil, he was Jesus and their Gardenvale neighbours were worshipping Satan.

Nurse feared boyfriend would one day kill her

On June 23 last year, Ms O'Brien told Sturt she feared he would kill her one day. He told her he would never hurt her.

Sturt and Ms O'Brien had been together since they were teens. He had a prior conviction for assaulting her in 2010.

In 2017, she said Sturt had been violent toward her for seven out of their 10 years they'd been together and a year later she told doctors his physical aggression and violence stopped three years earlier when he became motivated to change his ways.

A psychiatrist found Sturt had coercively used violence and threats of violence and suicide earlier in their relationship to mitigate a belief she would abandon him.

But he said there was no evidence the fatal attack was motivated by those same factors, finding he had delusional beliefs including that by killing Ms O'Brien he was saving humanity.

He attacked her in their bedroom on June 25 last year.

She ran from the room and grabbed a pair of scissors but he overpowered her, struck her with the scissors and smothered her with a pillow.

He tied tracksuit pants around her neck, showered and placed her credit card on her chest before leaving.

Caitlin O'Brien's family hopes Shea Dylan Sturt gets the help he needs. Source: Facebook

He spoke to police outside Flinders Street Station, confessing he had killed Ms O'Brien.

Sturt told police he'd been manic for a few days. When officers told him he would be charged with murder he replied "cool".

Justice Christopher Beale told the Supreme Court on Wednesday that Sturt was remorseful.

Sturt told doctors using cannabis was "like a cure-all" and it "made me treat Cait better".

Justice Beale found there was a reasonable prospect Sturt could be rehabilitated.

Martine O'Brien says she hopes to make nursing her sister's legacy.

"She was a compassionate, lovely nurse. She was just marvellous," she said. 

If you or someone you know is impacted by sexual assault, domestic or family violence, call 1800RESPECT on 1800 737 732 or visit 1800RESPECT.org.au

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