Birmingham man Ricardo Morrison, 22, has been jailed for life with a minimum term of 24 years at Manchester Crown Court after being found guilty of the murder of his teenage girlfriend, model Amy Leigh Barnes.
Morrison used a six-inch kitchen knife to attack Miss Barnes, 19, leaving her dying in a pool of blood at the house they shared in Farnworth, near Bolton, Lancashire.
His mother, Melda Wilks, 50, a policewoman for almost 30 years, was cleared by the jury of assisting an offender.
She allowed him to wash his bloodstained clothes after he fled Bolton to the family home in Rubery, Birmingham, hours after the attack on November 8 last year. She claimed she believed her son when he told her he had not harmed Miss Barnes.
"I was not thinking as a police officer but as a mother," she said.
Morrison was convicted following an 11-day trial at Manchester Crown Court. His mother was cleared 30 minutes later.
The jury had been out for three hours and 19 minutes when they returned the guilty verdict.
Trial judge Mr Justice MacDuff warned the packed courtroom there was to be no reaction when the verdict was given.
Morrison, clutching a bible, bowed his head, put one hand to his face and appeared to begin weeping. His mother, sitting separated by a security guard between them, turned away in tears. Morrison slumped to his seat with his head down, held in his hands.
The victim's mother, Karyn Killiner, clutched the arm of her husband John, while Miss Barnes's father, Andrew Barnes, smiled while holding hands with his new partner Dawn at the back of the court.
Morrison's violent history of attacking his partners and other young women was revealed for the first time following his conviction
In chilling similarities to his fatal assault on model and actressMiss Barnes, Morrison repeatedly attacked an ex-girlfriend who was too scared to give evidence against him in his murder trial.
He twice bit her on the face and after one assault sent her a text saying: "I hope you die of cancer, just like your dad."
And less than a month before he stabbed Miss Barnes, 19, to death with a six-inch kitchen knife, he attacked five women, headbutting and punching victims in the face in a London nightclub.
Described in court as a "phoney and a bully", Morrison has four previous convictions for assault and one for harassment on his ex-girlfriend, aged 23, from Birmingham. He was never sentenced to custody and broke a restraining order.
The jury at Manchester Crown Court was not told of his violent past - or that he faced five charges of grievous bodily harm for the nightclub attack.
Mr Justice MacDuff ruled the details would prejudice a fair trial and Morrison faced overwhelming evidence of his guilt anyway.
Wilks collapsed to the floor after her son was found guilty. When the jury returned to court to clear her, Morrison did not return to the dock.
Wilks left the dock weeping and was helped from court by one of her legal team.
Earlier, after Morrison was found guilty and the jury had left the courtroom, he sat pulling his hair out with his hands. He stormed down the steps to the cells when security guards went to remove him from the dock.
Outside court, Miss Barnes's family hugged each other in tears.
Miss Barnes, who was privately educated, was studying fashion and drama and had modelled for Cosmopolitan and Nuts magazines and also appeared in Channel 4 soap Hollyoaks.
But her boyfriend was described as arrogant and controlling, subjecting her to terrifying abuse during their stormy nine-month relationship.
They first met each other through Facebook and he soon moved from Birmingham to Bolton to live with Miss Barnes and her mother and stepfather, Karyn and John Killiner.
But his true nature was revealed while her parents were on holiday. Morrison held a knife to her throat, the police were called and he ran into the street with the blade.
Morrison was asked to leave the family home. Miss Barnes's grandmother took them in at her two-up, two-down terrace house in Farnworth, just outside Bolton.
On the morning of November 8 her grandmother left the house for work, leaving the young couple alone in the house. Morrison then attacked Miss Barnes, punching her, spraying an aerosol in her face and slamming a door on her arm. He left to go into Bolton, locking her in the house.
The row continued by text message. She called him a "wife beater" and told him the relationship was over. She cut off his mobile phone and he texted her back: "Evil bitch."
When he returned to the house, he picked up the knife from a block in the kitchen and launched the attack. Her face was slashed open from the corner of her mouth to her right ear and she was stabbed with "severe force" all over her body. Then he left her for dead.
In a harrowing recording of Miss Barnes's 999 call, her screams and sobs were heard by a hushed courtroom as she begged the operator for help, gasping: "He's stabbed me to death... my boyfriend, please help me. I can't breathe! I've been stabbed! I'm dying!"
Andrew Barnes, her father, who had been summoned to the house by her worried family, then arrives to find his daughter on the floor in a pool of blood.
With the phone line still open, he is heard to say: "Amy! Amy! Amy! What's happened, Amy? Are you all right? Amy, what have you done?"
Morrison fled to his mother's house in Birmingham, where she washed his bloodstained clothing - destroying forensic evidence.
During the trial Morrison, who had football trials for Birmingham City, claimed to be a successful young businessman and "woman pleaser", but in reality he was "profoundly two-faced", a "phoney and a bully", the court heard.
Miss Barnes enjoyed going to nightclubs in Manchester frequented by professional footballers - much to Morrison's annoyance. He once sent her a text saying he "hoped she got raped".
Miss Barnes told friends that Morrison, to whom she referred as "psycho", had been beating her up for months, held knives to her throat and threatened to kill her.
With the help of her mother, she had been to see a domestic violence project but was not yet ready to leave Morrison, the court heard.
A follow-up appointment was made but five days later she was dead.
Senior investigating officer Detective Chief Inspector Andy Peach said: "This was a brutal murder. Morrison repeatedly stabbed the person he was supposed to love, causing the horrific injuries that ultimately led to her death.
"Amy was her parents' only child and her death has devastated the whole family. I don't think anyone can contemplate what it must be like for a father to find his daughter like this.
"We don't think it is the first time Morrison hurt Amy. I hope this encourages anyone who is a victim of domestic abuse to speak out.
"At GMP (Greater Manchester Police) we have specially-trained officers who can support victims from the initial report and throughout the whole process."
Speaking outside court, Mrs Killiner said: "Ricardo Morrison stole our daughter and destroyed our lives. Amy was a beautiful person inside and out. She had her whole life ahead of her. She was trying to get away from Morrison when he killed her.
"For the past two weeks we have had to see him every day. He has been cocky and arrogant despite it being clear from the start he was responsible for Amy's death.
"He has previous convictions which demonstrate he is an evil man. Amy was our life and now our life will be devoted to ensuring Amy's memory lives on."
Detective Chief Superintendent Jane Antrobus said: "This man was not someone you could predict what he was going to do.
"The sentence of 24 years is a sentence that needed to be passed to keep that dangerous man off the streets. She (Amy) trusted this man and that trust was severely broken."
* A Facebook tribute group to Amy Leigh Barnes can be found here.