Buying a car with a lien

I want to buy this car from a private seller. He has a lien on it but needs my money first to pay it off. I like the guy but want to keep my interest safe. I live in California. Is there a way to do this so it helps both of us? I do not want to lose this deal because these cars are hard to find and this one is in great condition. (93 Stealth TT)

Have him give you a bill of sale until he pays off the lein, that way you have proof that you paid for the car.