Indiana Code Title 6. Taxation § 6-4.1-12-5

Sec. 5. (a) If one (1) of the conditions listed in subsection (b) of this section exists, the department of state revenue may, with the advice and approval of the attorney general, enter into a compromise agreement concerning the amount of any inheritance tax, or interest charges on delinquent inheritance tax, to be collected under this article.  The department may enter into such an agreement with the personal representative of a decedent's estate or with the transferee of property transferred by the decedent.

(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.