The teenage boy who murdered Ann Maguire had threatened to kill the teacher for months before he stabbed her to death and even showed pupils his knives on the day of the attack, a court has heard.
After he pleaded guilty to murder today, the prosecution showed Facebook messages dating back to Christmas showing his intention and revealed that on the morning of the stabbing, he told classmates he planned to kill Mrs Maguire and two other teachers, including a pregnant woman "so as to kill her unborn child".
The boy, who cannot be named for legal reasons, was only 15 when he stabbed her to death at Corpus Christi Catholic College, in Leeds, and his parents said they were "at a loss" over his motive.
Witnesses reported that he seemed "pleased" after the brutal attack in April and he told a psychiatrist it made him "happy".
"I had a sense of pride. I still do," the defendant said according to lawyers. "It's kill or be killed. I did not have a choice. It was kill her or suicide."
He admitted the killing at Leeds Crown Court today and is awaiting to hear his sentence.
Mrs Maguire’s husband, Donald, and her daughters, Emma and Kerry, were in court for the hearing, when the defendant looked straight ahead and showed no emotion as he admitted murdering Mrs Maguire.
The court heard harrowing details of the attack, when the teacher was stabbed repeatedly in the back and neck even as she tried to run away.
Paul Greaney, a lawyer for the prosecution, told the court his family were "decent people and responsible parents".
"They are at a loss to understand how and why their son has turned out as he has and they have co-operated fully with the police and with the prosecution," he added.
In pictures: Leeds school mourns Ann Maguire's death
In pictures: Leeds school mourns Ann Maguire's death
1/8 School mourns teacher's death
Steve Mort, head teacher of Corpus Christi Catholic College, reads the hundreds of tributes left in honour of slain teacher Ann Maguire in Leeds
2/8 School mourns teacher's death
Keiran Sykes, the deputy headteacher of Corpus Christi Catholic College, reads the hundreds of tributes left in honour of slain teacher Ann Maguire in Leeds
3/8 School mourns teacher's death
Amanda Gledhill, a former pupil of Corpus Christi Catholic College, grieves next to the hundreds of tributes left in honour of slain teacher Ann Maguire in Leeds
4/8 School mourns teacher's death
A photograph and flowers hang on the fence outside Corpus Christi Catholic College in tribute to slain teacher Ann Maguire in Leeds
5/8 School mourns teacher's death
A candle burns next to a book of condolence for teacher Ann Maguire at Corpus Christi Catholic Church in Neville Road in Leeds
6/8 School mourns teacher's death
A crucifix and school tie hang on the fence outside Corpus Christi Catholic College in tribute to slain teacher Ann Maguire in Leeds
7/8 School mourns teacher's death
A drawing outside Corpus Christi Catholic College in Leeds, after much loved teacher Anne Maguire was stabbed to death in front of her pupils
8/8 School mourns teacher's death
A nun comforts people outside Corpus Christi Catholic College
"It follows that this is not one of those cases in which a defendant's actions may find a degree of explanation in his family circumstances.
"On the contrary, (the boy's) family life was marked by love and support."
He was a pupil in Mrs Maguire's Spanish class and his academic reports “had generally been positive”, Mr Greaney said.
But although his parents or teachers saw nothing to indicate a risk of violence, the boy had told other children he hated Mrs Maguire and wanted her dead.
Mr Greaney told the court: “Late on the night of Christmas Eve 2013 and into the early hours of Christmas Day, the defendant exchanged messages with a friend on Facebook.
“In those messages he spoke of 'brutally killing' Mrs Maguire and spending the rest of his life in jail so as not to have to worry about life or money.”
Two months before the murder, one Facebook message shown to the court said: “The one absolute f****** b**** that deserves more than death, more than pain and more than anything that we can understand.”
On the morning of the attack, the boy reportedly told other pupils he was going to stab Mrs Maguire, even showing them the knives he was carrying along with a bottle of Jack Daniels "to celebrate".
Mr Greaney said he "winked" at a fellow student before entering her classroom and one witness said there was no expression on his face as he stabbed her.
Mrs Maguire had been leaning over looking at a pupil's work when he attacked her from behind with a "large kitchen knife", stabbing her in the neck and back.
She attempted to run away but was chased by the boy, who "stabbed her as she sought to escape", Mr Greaney said.
Holding a bleeding neck wound, Mrs Maguire ran to her friend and colleague Susan Francis who took her out of the corridor into a side room, holding it closed with her foot.
After the attack, the murderer told his classmates "good times" and calmly chatted to teachers and pupils "as if nothing had happened".
Outlining the psychiatric reports, Mr Greaney said the boy was "currently highly dangerous and has psychopathic elements to his personality".
The languages teacher, 61, was months away from retiring when she was attacked in the classroom in front of terrified pupils.
Her death sparked an outpouring of grief in Leeds and a renewed focus on the violence and threats teachers face throughout the UK.
More than 300 pupils and teachers attended a memorial service in her honour and a mass of floral tributes were left outside the school gates after the tragedy.
The Pope also contacted the Catholic family with a message of condolence following Mrs Maguire’s death.
It was thought to be the first time a teacher has been stabbed to death in a British classroom, and the first killing of a teacher in a school since the 1996 Dunblane massacre.
She started at Corpus Christi as a student teacher and the school held a celebration of her 40 years' service last year.
Mrs Maguire had moved to working four days a week ahead of her planned retirement in five months' time.
In a statement, her family paid tribute to their “shining light”, who “brightened the world for so many of us”.
They added: “A loving wife, the best mother, a treasured sister, a true friend. This horrific happening has robbed us of all of this and so much more.
"We are devastated. Her selfless, genuine, caring nature will remain with us eternally.”
Additional reporting by PAReuse content