As far as I know, if the vehicle has been purchased against a bank loan, the owner cannot sell it out as documents of the vehicle are with the bank and the owner will need to get hold of them by clearing his loan first. On the other hand, if the seller has the documents, sells the car to you and the Isthimara gets transferred to your name, you should not worry if the person carries a loan on the vehicle or the vehicle was carjacked.