Wow dude, the guy is running away from you. You are almost screwed. I don't know the laws in MA, but unless you have it in writing that the lean will be payed off by the seller, it looks like you might be paying the lean off. I don't even know what to suggest. Maybe call a lawyer, and return that bucket you purchased.

This, along with that cluster tamper dot, all the damage to the car from your previous posts, makes me think that you got screwed, and will continue getting screwed.

Go to your local police precinct or DMV and start asking questions. Maybe someone will be able to point you in the right direction. You basically need to get hold of the bank that issued the Lean. Try to find where this guy lives maybe. I don't know. I just hope you bought the car cheap, like really damn cheap, as in no hopes of ever selling it cheap.