On a tip off, police, disguising as customers, got in touch with one Pratap Pal Singh to buy the 350-year-old cannon from him.
Though Singh quoted the price for the 20-inch artillery gun weighing 25 kg at Rs 1 crore he later brought it down to Rs 65 lakh.
"Singh later went to Panipat and brought the cannon, along with his two accomplices Sanjay Gupta and Vijendra Chauhan, to the city", said DCP Dhananjay Kulkarni, adding they were picked up yesterday.
The trio have been booked under Arms Act and Antiquities and Art Treasures Act, he said.
According to police, Singh claimed that the cannon was made up of 'Ashtadhatu' (eight metals) and was his ancestral property.
The holder of such antiques must have licence and need permission to sell them, police said.
Police will rope in the Archaeological Survey of India (ASI) to ascertain Singh's claims.
