30 bombs were recovered on Saturday from a village pond in Bihar's Kishanganj district after local residents informed police about them.
The recovered bombs, which somehow became loose and surfaced on the water, were kept in a sack and dumped in a pond at Matiari village under Pothia police station of the district, police said.
"The recovered bombs were country-made but powerful ones. They had become inactive after being in water for a long time. It seems criminals had dumped them in the pond either to hide or to escape from being caught by the police," said Pothia Station House Officer (SHO) Akhilesh Kumar.
The SHO said three criminals were killed and a few others injured when few bombs exploded in the area on November 30, 2014 while they were planning to commit a crime.
He said that the gang of criminals had come from West Bengal to commit crimes and could have dumped the remaining bombs in the pond while trying to escape from the area.