A hand grenade was found in a pit in the old judicial complex on Old GT Road on Monday afternoon.
The incident came to light when Manisha Kashyap, a police department employee who lives in a house alongside the complex, noticed three unidentified youths digging a pit. Suspecting something fishy, she informed the police control room.
Policemen on a bike rushed to the spot and identified the hand grenade kept in a blue polythene bag. A case was registered under sections 3 (repeal of portions of Act 12 of 1875) and 4 (definition of explosive material), of the Explosives Act.