I have a piece of property in California that has a mobile home on it that is not owned by me. The bank recently repossessed it. Can I put a lien on it for back rent and current rent if I did not have a contract with prior owner? (mobile was on property when I purchased it) Does the bank have to pay me rent while they sell or are in the process of removing mobile?

Mobile homes are *not considered real estate* under law; they are simply personal property like a vehicle. I think you are pretty much out of luck in this case.

There may be laws about squatters in California civil code if people lived on your property in the mobile home while you owned the land.

Well, since it is your property you don't have to let them on without them trespassing.