I would call that car stolen regardless if the person it was stolen from is alive.
Of course, a stolen car is a stolen car. And stealing it in the first place was unjust. If we can correct this injustice by having the thief return the car to its original owner and return the money to the good faith buyer, then all is well. But sadly it is not possible to correct all past injustices without adding further injustice. Two wrongs don't make a right.
What alternative would you suggest?
RE: War, taxation, and ultimately government itself will eventually go the same way as slavery and human sacrifice