Four migrant labourers werecrushed to death and three others seriously injured when a speeding tempo ran over them on Mumbai-Ahmedabad Highway on Saturday, police said.The incident took place at around 3 am near Parol village in Vasai tehsil, where the speeding tempo knocked down a group of migrant labourers from Rajasthan, who were travelling towards Mumbai on foot, police PRO Hemant Katkar said.While four were crushed to death, three others sustained serious injuries and were rushed to a nearby hospital, he said.The tempo driver, who initially fled the scene, was subsequently arrested by the Virar police, he added.A case under sections 304(A) (death by negligence), 279 (rash driving) and other relevant provisions of the Indian Penal Code and Motor Vehicles Act was registered against the driver, he said.The deceased were identified as Ramesh Mangilal Bhat (55), Nikhil Pandya (32), Naresh Kalasuva (18) and Kaluram Bagore (18), he said, adding that their bodies have been sent for post-mortem.The victims were among thousands of migrant labourers from Gujarat and Rajasthan who were headed to their hometowns on foot, but were stopped at Maharashtra border and sent back.