The ‘weird’ loner who murdered teacher Ann Maguire: He confided in friends but adults suspected nothing

• Boy, 16, admits murder of Leeds teacher Ann Maguire

Cornick, who is 16 now but was 15 when he stabbed his teacher to death, was taking GCSEs at Corpus Christ Catholic College but had already passed five exams a year early.

At the time of the murder, he had never been convicted of a criminal offence and his school reports were positive.

A judge heard that adults had no reason to foresee the violence he was capable of but the court was also told that he confided in children about his deep hatred of Mrs Maguire and his desire to kill her and other teachers at the school.

The judge accepted that the boy’s mother and father were “decent people and responsible parents” who are still “at a loss to understand how and why their son has turned out as he has”.

Prosecutor Paul Greaney QC said: “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, (Cornick’s) family life was marked by love and support.”

The court heard the boy’s mother and father divorced when he was young but “both parents worked hard to maintain a loving relationship with the defendant and to foster a close relationship between him and his siblings”.

An expert who looked at the teenager’s school records concluded “that they are remarkable for the achievements and academic progress the defendant appears to have made”.

He said the boy was happy and made good progress at primary school and when he joined Corpus Christ his parents received a letter congratulating him on his effort.

Mr Greaney said: “He was seen as reserved but amicable, enthusiastic and a conscientious member of the pupil group.”

In Year 7 his tutor said he was “a delightful pupil who always gave his best and was pleasant, polite and cooperative with a 100% attendance”.

The court heard that the school recorded only five incident of misbehaviour in his five years there.

Mr Greaney said two were minor and the other three occurred about two months before the killing and related to his “imagined problems” with Mrs Maguire.

The court also heard that the boy collapsed when he was 12 and was diagnosed with diabetes. His mother noted some self-harming between 2011 and 2012 but this seemed to stop.

And, in 2013, his parents reported minor stealing from home and he discovered his diabetes would bar him from his intended career in the army.

Mr Greaney said: “Nonetheless, there was nothing that might have indicated to his parents or teachers that there was any risk of violence, let alone homicidal violence.”

But, the court heard, he harboured a deep, irrational hatred of his Spanish teacher and told a number of pupils of his intention to hurt her or even kill her.

He told one friend of her “being killed in unpleasant circumstances” and another that he had been carrying a knife.

Police found many pictures of knives on his mobile phone.

The boy also talked of his dislike of another teacher, who was pregnant, and later spoke of harming her unborn child.

One girl said that “Mrs Maguire had treated the defendant as she treated everyone else but (he) still disliked her”.

Last Christmas - four months before the murder - he messaged a friend on Facebook talking of the “brutal killing” of his teacher.

In February this year - two months before the killing - Mrs Maguire banned the boy from going on a school trip for failing to do his homework but he went anyway.

At a subsequent disciplinary meeting, the teenager walked out and was disrespectful, the court heard. His parents were called to school and, according to the boy’s father, he made plain “that he hated Mrs Maguire”.

He was placed in internal exclusion at Corpus Christi.

Many pupils at Corpus Christi Catholic College were surprised when they found out whom the police had arrested.

They thought of him as a quiet boy who liked playing computer games at home.

One 16-year-old girl said he rarely spoke and many of his contemporaries thought he was ‘’a bit weird’’.

‘’He was in my class and he would sit on his own and just stare straight ahead,’’ she said. ‘’No one really noticed him. That’s why it was such a big surprise.’’

Others said he was a bright pupil from a ‘’nice’’, middle-class family.

‘’They’re just a normal family,’’ a teenager said. ‘’Can you imagine what they are thinking today? He’s a smart kid too - all top grades. He was good at drawing too.’’

One girl said: ‘’I think it’s come as a shock to everyone to hear he’s been arrested. I didn’t know who he was until someone explained and I realised I knew him. He’s just a quiet one.’’

One 16-year-old who has known the boy since primary school said: ‘’I could not believe it when I heard his name. He is just so quiet. He’s an emo but he’s an ordinary, quiet bloke.’’