Ann Maguire was aged 61 when she was murdered. She had spent her entire working life at the school and was due to retire in September. Her funeral service was held at the Church of the Immaculate Heart of Mary on 16 May 2014.
Among those paying tribute to Maguire were Pope Francis, Prime Minister David Cameron, and Frances Lawrence, widow of London headteacher Philip Lawrence who was murdered in 1995.
An Educational Trust offering bursaries in artistic subjects was set up in her name.
Will Cornick's parents were separated, yet both were described as supportive. He joined Corpus Christi in Year 7. His former Head of Year described him as polite and with 100% attendance. Prior to the murder, he had only five incidents of misbehaviour in four-and-a-half years at the school, and no criminal record. Classmates described him as academically gifted, and unlikely to cause trouble.
A personality change in Cornick had been noted following a collapse on holiday in Cornwall, after which he was diagnosed with diabetes. He had briefly self harmed due to the condition. In 2013, he was upset at not being able to join the Army due to his diabetes. On Christmas of that year, he sent a Facebook message to a friend in which he talked about "brutally murdering" Maguire.
Cornick admitted to psychiatrists that he had been planning the murder, and intended to do it four days earlier.
He stabbed Maguire seven times with a 21 cm knife in class on 28 April 2014, and then chased her into a room where another teacher blocked the door to keep Cornick out. He then returned to his class and told a friend that it was a shame that he had not killed Maguire. She later died in hospital.
Cornick admitted he planned to kill two other teachers, intending to also kill the unborn child of one of them.
On his arrest, Cornick was detained at Wetherby Young Offenders Institution near Leeds, but due to concerns for his safety he was transferred to HM Prison Hindley near Wigan.
Due to an anomaly in British law, although it was illegal to name or identify Cornick during his trial due to him being a minor, it was legal to name him before the trial began. The tabloid newspaper The Sun named him the day following the murder.
Psychiatrists said that Cornick possessed “a gross lack of empathy for his victim and a degree of callousness rarely seen in clinical practice” and that he “presents a risk of serious harm to the public and that this risk is present for the foreseeable future. The risk is of grave homicidal violence and this could easily involve the use of a weapon. The risk is immediate and unpredictable and could cause serious and lethal injury.”
He was imprisoned at Leeds Crown Court for a minimum of 20 years.
Mr Justice Coulson lifted the restrictions on naming Cornick, saying that the action would have a "clear deterrent effect". Cornick's defence lawyer Richard Wright brought up that this would be illegal under Article 2 of the European Convention on Human Rights due to immediate threat to his life, which the judge countered with Article 10, freedom of expression.
Penelope Gibbs, who chairs the Standing Committee for Youth Justice (SCYJ) umbrella group of charities and campaign groups, said the sentence was too long and more emphasis should be placed on rehabilitation. There is concern that the minimum tariff is excessive because the brain of a 15-year-old is not mature, neuroscientists do not currently understand fully how the brain matures during adolescence and rates of maturity vary between individuals. Deborah Orr wrote:
At 15 or 16, a human brain is far from fully developed. The volatility of teenagers is partly a consequence of the accelerated neural sculpting that goes on in these years. (...) Cornick – or any person who commits a crime at 15 years of age – is not a fully developed human being. The man serving Cornick’s sentences will have a materially different brain and mind from the boy who committed the crime. Child criminals should be treated differently to adult criminals for this reason. (...) Cornick should have been given a sentence that pertained until his adulthood, at which point a judge would have been in a realistic position to receive information about the manner in which the rest of his sentence should be conducted. No one, not even a judge, can know at this point what kind of a man Cornick will become.
Allegedly other western European nations would be less severe though the tariff appears to be in line with tariffs for other UK child murderers.
In January 2015, Cornick lost an appeal against his sentence.