This will vary from state to state, and depends on if this is a state or federal offense. Your friend needs to consult an attorney, and remember, that's privileged communication.
Different crimes have different statutes of limitations, and the SOLs vary from state to state. Federal offenses vary, too. The SOL has much to do with the nature and extent of the crime.
depending on which state and the nature of the crime in business it can be 3-6 years from discovery of the crime. If tax related it may be 10 years or more
