To CID agents in Elakiri
If they can gain access to his mobile number, there is a chance to reset iCloud password, then gain access to icloud account on the web and access messages, some emails and photos on the phone. (Usually this is very easy to do)
Apart from this, they can recover almost all accounts linked to phone numbers.
We can reset iPhone PIN with iCloud but that will erase all the data in the phone. Even if the current device is locked, If we login to a new iPhone using the same icloud account, most of the data will be automatically synced to the new phone.