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.
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.
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.
He attended lessons as normal. After morning break, he went to the top floor for his Spanish lesson. Half way through the lesson, he stabbed Maguire seven times in the back and neck with a 21 cm knife in class on 28 April 2014. One cut straight through her jugular vein. He then chased her into the corridor where Susan Francis (Head of Languages), alerted by screams, ran to help her. She separated and shielded Maguire from Cornick. Francis got Maguire away into another room where she held the door shut 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.
In January 2015, Cornick lost an appeal against his sentence.
In November 2017 an inquest is being held into Ann Maguire's death.
