Transfer of Title: How to Locate Vehicle in Another State

My question involves a consumer law issue in the State of: Idaho

Brief summary: I loaned a friend $2000 to purchase a vehicle (witnessed and signed promissory note to repay loan) in California. He drove the vehicle to Pocatello, ID where he left it with a friend of a friend. He subsequently was arrested and imprisoned in AZ and the vehicle is still in Idaho. Because he's now unable to pay me back for the vehicle, he's signed the title over to me so I can get it and resell it. Unfortunately, he doesn't know the person's last name or address where he left it. The friend he went to visit knows the info but won't give it to me.

I have the CA license plate number, the VIN and the (worthless?) title. What's the best way to try and locate and repossess the vehicle. Oh, in the meantime, the person with whom he left the car has been arrested and incarcerated as well.

I'm just a kind hearted senior citizen who trusted the wrong person.

Any suggestions would be appreciated. I haven't contacted the police there yet because I wasn't sure what to report.

Transfer of Title: How to Locate Vehicle in Another State