The deceased has been identified as 15-year-old Rajendra Pun of Sukakhola, Korchawang-8.
The injured youth has been identified as 15-year-old Bishal Pun. Police suspect the explosion took place while they were fishing in the river.
Deputy Superintendent of Police Krishna Pyara Pokharel said the socket bomb was planted during the insurgency.
Train with 53 bogies carrying blast arrives in Janakpur