BINGHAMTON, New York (AFP) - US police Saturday sought to discover why a jobless immigrant snapped, going on a murderous rampage in the centre where he learned English, mowing down 13 people before killing himself. The bespectacled gunman at the heart of the tragedy in the quiet, small New York town of Binghamton was identified as Jiverly Voong, 41, of Vietnamese descent, who until early March had been taking classes at the American Civic Association. Early Friday Voong, who had legally changed his name from Wong, donned body armour, blocked the centres back doors with his car and then burst into the front of the building in a hail of gunfire, police said. Without uttering a word, Voong strode into a classroom where an English lesson was being held, and shot dead 13 people, injuring another three, before turning the gun on himself, police chief Joseph Zikuski said. The alarm was raised by a receptionist, hailed as a hero by the police chief, who played dead after being shot in the stomach. She then crawled under her desk to call 911 on her cell phone. She and the other three injured were Saturday still being treated in hospital. Two were in a critical condition. The small community, 135 miles northwest of New York City, voiced shock Saturday at the outburst of violence, especially angered that it had happened at a centre trying to help new immigrants. The names of the victims have not yet been released, but mayor Matthew Ryan said Binghamton authorities had had inquiries from nine countries and two consulates about the safety of their nationals. Police said they had interviewed the killers parents and sister, with whom he shared a home in the nearby town of Johnson. President Barack Obama, speaking in Strasbourg on the sidelines of NATO summit, said: I am heartbroken for the families who survived this tragedy. It just underscores the degree to which in each of our countries, we have to guard against the kind of senseless violence that tragedy represents.