The deceased have been identified as Roshan Kumar (12) and Priyanka (16) who were the children of Yogendra Yadav, a resident of Jangipur village under Barbigha police station of the district, Superintendent of Police Rajendra Kumar Bheel said.
The incident occurred when Roshan was bathing in a private pond located in front of his house but he went into deep waters and started drowning.
Seeing her brother drowning, elder sister Priyanka jumped into the pond to save him but both drowned, the SP said.
Villagers fished out the bodies of both the brother and sister from the pond, Bheel said adding that bodies have been sent to Munger sadar hospital for post-mortem.