CHENNAI: Three engineering college students were killed on the spot and one sustained injuries when the two-wheelers on which they were riding, were knocked down by a mini-lorry near Kovalam on the East Coast Road (ECR). Police sources said the students -- Sakthivel (20), Ravikumar (20), Sasikumar (20) and Prakash (22) -- were studying at a private engineering college in Sholinganallur on the OMR. They were returning on two motorcycles after visiting a friend in the wee hours of today, when they were knocked down by the mini lorry near the Kovalam-ECR Junction. In the impact, all the four--travelling on two-wheelers--were thrown off from their vehicle. While three of them died on the spot, Prakash, who sustained serious injuries, was admitted to a hospital. The van driver, Karthik, fled the scene after abandoning the vehicle and police have launched a manhunt to trace him.