‘She should’ve been safe’
A psychotic killer who murdered his nurse girlfriend "to save humanity" has been jailed for at least 16 years.
Caitlin O'Brien, 31, had suffered years of violence at the hands of her boyfriend, Shea Sturt, and had only weeks earlier survived surgery to remove a brain tumour when she was killed.
Sturt, 33, stabbed at his girlfriend with scissors, suffocated her with a pillow before tying a pair of tracksuit pants tightly around her neck to make sure she was dead on June 25 last year.
Sturt admitted to carrying out the frenzied killing during a cannabis-induced psychosis where he believed his partner of more than a decade was a "psychopath" who killed people and a witch from a Marvel movie.
Supreme Court Judge David Beale said the murder of Ms O'Brien cut short the life of a passionate, much-loved nurse.
"You murdered her in her own home, where she should have been safe," Justice Beale said.
The court earlier heard Ms O'Brien had suffered increasing physical by Sturt and colleagues would witness her crying at work and covered in bruises.
Sturt had been admitted to the Alfred for psychiatric care three times in the months leading up to Ms O'Brien's murder.
His last admission was just days before she was killed when Sturt assured her: "I would never hurt you".
On the morning of the killing, Sturt said he and Ms O'Brien sat on their bed and "discussed the end of the world" before she became scared and tried to escape him.
Immediately after her death, Sturt riffled through Ms O'Brien's wallet and laid a bank card on her naked body to signify "you don't owe me anymore", a pre-sentence plea hearing heard last month.
The young nurse had been financially supporting Sturt, who had been unemployed for almost all of their relationship since the couple meet at TAFE as teenagers.
Following the murder, Sturt walked around the city and sought advice from homeless people before telling two PSO officers - "you have to arrest me, I've just killed my girlfriend".
He said murdering Ms O'Brien was "the morally right thing to do to save humanity".
When detectives later told him he would be charged with Ms O'Brien's murder, he responded: "cool".
Justice Beale said Ms O'Brien's loved ones had suffered greatly.
"You really can't understand the distress, loss, agony and disbelief unless you experience it," Ms O'Brien's father said in a victim impact statement.
Family members of the slain young woman said they "lost two people" the day Sturt murdered Ms O'Brien.
Martine O'Brien, Caitlin's sister, said she hoped Sturt used his time in prison to "get better" and rehabilitate himself.
"That's what my sister would have wanted," Martine said.
"She would've wanted him to get help and I really hope he does that," she said.
Martine O'Brien said the family was "very happy" with Justice Beale's sentence.
She said her sister was a vibrant young woman who would have done anything for the nursing community.
"She was a compassionate, lovely nurse,"
"She was marvellous, she was emphatic and vibrant," Martine O'Brien said outside court.
The family said they would like to make her legacy one of nursing and would be working with the Alfred and Caulfield Hospitals and other nursing charities to do so.
A forensic psychiatrist reported Sturt's increased cannabis use only worsened his mental condition.
Defence barrister, Tim Marsh, has earlier argued if not for the drug-induced psychosis "it's overwhelmingly likely that this offence would not have occurred".
Prosecutors had argued Sturt's decision to use cannabis was an aggravating feature but Justice Beale did not agree.
Justice Beale took into account Sturt's early guilty plea, remorse and good prospects of rehabilitation in sentencing him to 22 years behind bars.
He will be eligible for parole in 15 years with time already served.
*For 24-hour domestic violence support call the national hotline 1800RESPECT on 1800 737 732 or MensLine on 1800 600 636.
Originally published as 'She should've been safe': Sturt berated over brutal murder