Argentinian student Steven Grisales stabbed after asking youths to stop throwing conkers at him A foreign student was killed after pleading with north London youths to stop throwing conkers at him, police have revealed. Steven Grisales, 21, remonstrated with a group in Edmonton last week as they lobbed horse chestnuts at him while he made his way to a train station. One of the group pulled a knife and stabbed Grisales through the heart. The student, from Argentina, arrived in London in July and was due to start a scholarship from Westminster College for a three-year architecture course. Grisales was taken to the Royal London Hospital where he died the next day. Four people have been arrested in connection with the killing. Two 15-year-old boys are in police custody at a north London police station after being arrested on Monday. A 19-year-old man and a 16-year-old girl have been bailed until next month. Police believe that the attack on 31 August was not gang related and Grisales did not know any of the males suspected of being involved in the murder. “Officers now believe the incident began after conkers were thrown at the victim as he made his way towards Silver Street railway station,” a Scotland Yard spokesman said. “He initially remonstrated with the youths but one of the suspects produced a knife and stabbed him.” Detective Inspector Richard Beadle, of Scotland Yard’s murder command, called for witnesses to come forward. “It happened in a busy residential area and we know there would have been a number of people in the area at the time of the attack,” he said. “We really need those people to talk to us.” Knife crime Crime Shiv Malik guardian.co.uk