Legal Question in Criminal Law in California

Re: Worked for 4 Years and then Fired after Backgorund Check

You're an 'at will' employee that can be fired any time for any reason, unless covered by a written employment contract or union CBA, or unless the firing violates the civil rights type laws.

More to the point, a company being bought out typically ceases to exist, everyone gets terminated, and the new company may then choose which employees they want to hire and keep. You were probably offered some separation/severance package as a result of the sale; if not, oh well. Unless the 'termination' is somehow illegal, your 'rights' haven't been violated to provide grounds for a lawsuit. Unless the company has a clear policy and schedule of paying severance or providing protection against such termination [in the sale agreement maybe], you have no 'rights' to payments.