Suspected militants might have kept the grenade there late last night, but the bomb squad of police defused it as soon as it was located this morning.
Authorities of the M M Higher Secondary School said some militant outfits had demanded a huge amount of money from the school, but that was not paid.
Official sources said some militant outfits had kidnapped a student of Don Bosco School near here about two weeks ago as the school authorities did not give the demand money. The boy was later freed following protests by social organisations, the sources said.