I Received A Ticket In The Mail For Running A Red Light In A Vehicle My Ex-husband Sold 2 Years Ago.

I'm in Memphis, Tennessee. I'm concerned about to what extent I could be held liable if the person driving the X-terra that my ex-husband supposedly sold 2 years ago. I received a camera ticket for running a red light in the X-terra that I thought had been sold. Apparently, the X-terra has been tagged in my name for the last couple of years. My ex has a body shop and occasionally flips cars to sell. I bought my son the X-terra when he turned 17. My son decided that he wanted to trade the X-terra for a Prius his father had. I got intouch with my ex-husband a week ago about the car still being in my name. The 1st story he gave me was he had power of attorney to sell the car. Why would he need a PoA to sell my vehicle? He agreed to send me a copy of the so called PoA. I never received anything. I spoke with my ex again this past Monday. I was asking to see the title. I was told that gave the title to a friend who was making payments to him for the X-terra. I told him it didn't make sense to hand over the title before the car had been paid in full. His reason for handing over the title is that this is the way it's done. He says he put one of us down as the lean holder. Once again, I asked for information and for him to get the tags off the X-terra and give them to me. Once again, I never heard from him. So, because he has a long history of lying, I don't know what to do from here. I have several questions. If I'm the leanholder, why am I not receiving the payments. I mean, I did buy the car. There's no question that he didn't know the car was being registered and tagged in my name. There's no question that he wasn't aware of the situation. He didn't expect me to find out. Now I need to know what steps I need to take to resolve this situation. Any and all advice will be appreciated.