Iowa Code § 183A.12
Persons subject to this chapter and first purchasers shall furnish any information needed to enable the council and secretary to carry out the provisions of this chapter. For the purpose of ascertaining the correctness of any information given to the council or the secretary under this chapter, the secretary may examine books, papers, records, copies of tax returns, accounts, correspondence, contracts, or other documents and memoranda the secretary deems relevant which are in the control of any person and which are not otherwise confidential as provided by law. The secretary may hold hearings, take testimony, administer oaths, subpoena witnesses, and issue subpoenas duces tecum in connection with the administration of this chapter.
Iowa Code § 183A.12
85 Acts, ch 199, §12