A 15-year-old schoolboy with a “worrying interest in knives” who stabbed another teenager through the heart on the way home from school has been given a life sentence with a minimum term of 13 years. Bardia Shojaeifard was convicted in April of murdering Alfie Lewis, 15, outside St Margaret’s primary school in Horsforth, Leeds, last November. Shojaeifard was 14 at the time of the killing. He admitted stabbing Alfie twice with a 13cm-long kitchen knife he had brought from home but denied murder, claiming he was scared for his life when he pulled out the weapon. He can be named publicly for the first time after the judge, Justice Cotter, lifted reporting restrictions preventing him from being identified on Friday. Cotter said lifting anonymity would help in the “vitally important debate about the scourge of knife crime, among young people in particular”. The judge said the public would be wondering how an “outwardly normal” young boy “from a loving and supportive family” could commit such an “extraordinary” crime “without forewarning or any warning signs save for some pictures of knives on his phone”. He said one witness described the attack as “vicious”, with Shojaeifard “trying as much as he could to inflict some sort of damage to Alfie”. He added: “Knives have stolen so many lives, and you and others must understand how dangerous this obsession is. Without your interest in knives Alfie would be here today.” A statement read by Alfie’s aunt, Emily Lane, outside Leeds crown court after the sentencing said: “There is no punishment that can be given that will take away our pain. Alfie, your mum loved you for 15 years and thought she would have you here for the rest of her life. We love you, we miss you and we will do for ever.” She said the family was devastated at the sentence handed out as it did not “demonstrate how serious the actions of Alfie’s murderer have been”. Earlier in the case, the prosecutor Craig Hassall KC said Alfie had been walking to meet friends when the defendant attacked him close to the school just before 3pm on 7 November. Hassall said Alfie was stabbed twice, once in the chest and once in the leg. A postmortem found that the fatal injury was a 14cm-deep wound that punctured Alfie’s heart. Hassall said all the witnesses were consistent in saying Alfie was not the aggressor that day.