The parents of tragic Harvey Willgoose today criticised his school's failure to act on "red flags" before he was stabbed to death, saying: "They let Harvey down." Harvey, 15, was killed by Mohammed Umar Khan, 15, - who had brought a hunting knife to school - while on his lunchbreak at All Saints Catholic High School in Sheffield. The killing took place in front of horrified children and teachers. An independent review into Harvey's death has found "several missed opportunities" to address