An 18-wheel trailer truck allegedly ran over three people, killing them instantly, on the outskirts of Amritsar Saturday. The dead include a woman and her son.Police said the trailer truck carrying iron girders was headed from Mahla toward Ajnala. The victims, who were on a motorcycle, were riding behind the trailer and were caught by surprise when it suddenly reversed. All three were crushed to death.The victims were identified as Raman, 23, his mother, Geeta, and a friend, Sunny, 27. Police sent the bodies for postmortem and detained the driver.Amritsar mayor Moti Bhatia, who was passing by, tried to help the victims but they had died on impact.