By the police in lower Assam's Kamprup (Rural) district today.
During routine checking at Amingaon near Guwahati, police halted a car travelling from Guwahati towards Rangiya and recovered the pistol, police said.
Nazrul Islam Haque hailing from Rangiya travelling in the vehicle was detained, police said.
Two others identified as Bitu Ali and Raju Ali with him escaped, the police said.
A search operation was on .