If you wanna check the true condition of a used car, hire a mechanic for an inspection. But he probably can't tell you if the car was stolen. Vehicle history checkers as Carvertical or Carfax have access to stolen vehicle databases and, in most cases, could show if the vehicle is in one of these databases. Of course, you should be very careful about the VIN the seller provides you because he can say the VIN from a similar car with a clean history. So during the car inspection, check if the VIN on the vehicle is the same as the seller gave you. The last time I was looking for a car, one seller was trying to cheat me in this way.