A woman was stabbed to death by her ex who wrongly believed she was having a relationship with his best friend or his brother.
Abid Mahmood, 35, turned up at Tamby Dowling's house armed with a knife months after the pair had split up.
Mahmood barged into her house in Oldham, punching her before knifing her. He stabbed Tamby eight times, with some wounds being inflicted close to her heart.
A friend of 36-year-old Tamby described the killing as an act of 'pure calculated evil', the Manchester Evening News reports.
Mahmood had taken a taxi to her home in Chadderton. He spent about two-and-a-half minutes in the house during the killing, before getting back into the taxi.
"I can hear screaming in my head, pray for me brother," Mahmood told the taxi driver after getting back in the car.
He later surrendered himself at a police station, and handed over the blood stained knife he'd used to kill Tamby, who was described as a 'beautiful, kind hearted soul'.
He told an officer that he had felt 'like killing someone'. Mahmood's face was described as being 'demonic' at the time.
Manchester Crown Court heard that he had suffered from 'extensive' mental health problems since he was a teenager and had been diagnosed with a schizophrenic disorder.
Mahmood pleaded guilty to manslaughter on the grounds of diminished responsibility, a plea accepted by the prosecution. He is currently housed in the secure unit at Prestwich hospital, receiving mental health treatment.
His barrister said Mahmood had 'begged' to be sectioned prior to the killing, and claimed he hadn't received adequate support.
Prosecuting, Jaime Hamilton QC said that there had previously been a 'series' of incidents where Mahmood had been 'aggressive and unreasonable' towards Tamby.
Prior to the killing, he had called Tamby 17 times.
Mahmood, who has previous convictions for violence and drugs offences, turned up at her home just before 7pm on November 8 last year.
Police and paramedics rushed to the scene but she was declared dead within the next hour.
In the weeks before, he had told mental health practitioners that his ex-partner was in relationships with people close to him, including his brother and his best friend, as well as his intention to harm himself or others.
Mr Hamilton said these were paranoid beliefs which were untrue. He argued that it was a premeditated crime and that Mahmood intended to kill his ex.
The couple split in March last year. The court was told the breakup came after Tamby described Mahmood's 'escalating' mental health issues.
Shalina Miah, one of Tamby's best friends, paid a moving tribute to her. She said: "Tamby was one of the most kind-hearted, fun loving, goofy people you could ever meet. She could have you in fits of laughter without even trying.
"She truly was a beautiful, kind hearted soul. She would not hurt a fly."
Two of her sisters also paid tribute to their sibling.
Stacey Hawley said: "My sister was a loving, kind and caring person, and would do anything for her friends.
"To hear my father howling and crying, while my mother said Tamby is gone, is something I won't get out of my head." Lisa Hawley added: "She was the kindest, amazing, fun loving sister, daughter, aunty, who meant the world to all of our family."
Defending, Frida Hussain QC disputed that he intended to kill Tamby, instead arguing he intended to cause serious harm. She said that Mahmood had been 'begged' and 'pleaded' to be sectioned prior to the killing, and had made 'genuine' and sustained' efforts to seek help.
"He could not resist the commands of the voices telling him to harm others," Ms Hussain said. "He was not given the treatment that he ought to have been at the time," she said.
She said his prescription had been reduced in the time prior to the killing. Sentencing is due to take place next week.
