about a title for my car?

[Mike]

well lets start i started to pay off my car and when i got the car from my buddie he signed me a bill of sale proving that he sold me the car i have the title but have not switched the names on it . i only owe him 240 for it and im paying 1000$ but no he wants the car back and he went to the dealer where he bought it from and got a copie of the title and the reg , so now can he take the car back and report it stolen as the title is in his name still but i have a bill of sale and i live in indiana what am i gonna do