Vinod (28), his wife Geeta (25), son Atul (5) and a relative Shailesh (20) were killed when the unidentified truck hit the motorcycle near Paridhipur village, they said.
Vinod's daughter Lalli (7), who was injured in the accident, has been admitted to a hospital nearby, officials said, adding that a hunt has been launched to nab the absconding truck driver.