An Uttar Pradesh roadways bus ran over as many as seven labourers in the Gautam Buddha Nagar district killing four of them and injuring the rest, police said on Thursday. “Three workers of Hero Motors Company were killed, and one other died during medical treatment after they were hit by a bus from the Noida Depot under Badalpur Police Station area. The bus has been seized and a search operation is underway to nab the accused bus driver,” said the police official.