Ind. Code § 6-4.1-12-5
(b) The department may enter into a compromise agreement under this section only if the department and the attorney general believe that a substantial doubt exists as to:
(c) After payment of the inheritance tax agreed to by the parties to a compromise agreement entered into under this section, the issue of the amount of tax to be collected may be reopened only if the agreement was entered into fraudulently.
As added by Acts 1976, P.L.18, SEC.1.