Hello Sir,
I understand the situation that you are in, but it is quite possible that your father issued blank cheques during his lifetime and the bank cleared the cheque because the signature were matching.
As per law you can not interfere with the investigation of the police but yes police can not deny to lodge an FIR, of police without lodging an FIR closes the case then you can go to the magistrate to file a case under section 156(3).
Also, bear in mind that if your father passed away inestate then you can file a partition suit to claim your share in the property.
Also apart from FIR you can file a declaration suit to obtain an order that the bank account be freezed till further order.
Regards