Apart from an AK-56 assault rifle, three magazines, a 9 mm pistol and 13 live cartridges were seized from Khan's house by the Anti Extortion Cell (AEC) of Thane Police, he said.
The assault rifle was lying at Khan's house for a long time, the official claimed.
He and some others had allegedly planned to kill Iqbal Attarwala, a former gang member, on the instructions of fugitive gangster Chhota Shakeel, the official said.
They were arrested before the plan could be executed.
Naim Khan is currently lodged in Thane prison, awaiting trial.
AEC sleuths are questioning Yasmin Khan as to why the weapons and ammunition were stored at the house, the official said.
She was today produced before a court in Thane which remanded her in police custody till July 11, he added.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)