Mumbai Nov 26 PTI The Cyber police station of Mumbai Crime Branch has begun probe into several confidential home department documents found in the Whatsapp chats of builder Sanjay Punamia and his son Sunny Punamia an official said on Friday The Punamia duo was arrested in July in connection with a Rs 15-crore extortion case in which former police commissioner Param Bir Singh and several others are also named as accused The official said the Special Investigation Team SIT formed to probe the cases against Singh had confiscated mobile phones of Punamia and the Whatsapp chats were found during the extraction of data from the devices In these chats some two dozen pages of home department documents marked confidential including a letter from the Central Bureau of Investigation in Delhi have been found he said Following this an FIR was registered against the Punamia father-son duo and others under sections 379 120 b of IPC as well as provisions of Indian Telegraph Act and IT Act at Marine Drive police station on October 20 on the complaint of an SIT official he added The Cyber police station of Mumbai Crime Branch recently registered separate FIR in this connection and have begun probe the official informed PTI DC BNM BNM BNM