The mishap took place when four boys slipped into the river while taking a bath, Superintendent of Police (SP) Sunil Kumar Nayak said.
While three boys, identified as Ritesh Kumar (18), Bittu Gupta (14) and Rohit Kumar (15), drowned, Raunak Kumar was rescued by the local people, he said.
The bodies were fished out and handed over to the families for last rites, Nayak said.
