Hello, my name is Kevin.
The first thing I would do is contact a lawyer. Do not be bashful about this, because YOU WILL SUFFER. I am not kidding here.
The lawyer will advise you (I would have the lawyer do this, just pay the freight) to contact the finance company or whom ever holds the loan & get things going with them. They will want their money.
I would also contact the local police & see if there are any laws in your area that might help you here.
Take care of yourself here brother. I mean it.
I paid a hefty price by being the nice guy many years ago, & I am still paying for it.
I'll give you a brief:
I was living in los angeles & thought I was in love. I helped a girlfriend (co-signed a loan) buy a car. She went out with the girls one night, got drunk & crashed the car. They left it where they crashed it with the open bottles in the car.
Guess who got arrested, slapped with drunk driving charges, property damage charges, & payment for the car. Did I mention I got fired from my job because I lost my license.
It took me 3 months to find this peach & 2 years with an attorney & thank 7-11 a video tape of these women crashing & leaving the scene.
Best of luck brother. CALL AN ATTORNEY