S.D. Codified Laws § 37-24-12
If the attorney general has reason to believe that a person has engaged in, is engaging in, or is about to engage in any act or practice declared to be unlawful by § 37-24-6 or has entered into a contract with a provision that is void and unenforceable under § 53-9-13, and he believes it to be in the public interest that an investigation should be made to ascertain whether a person has in fact engaged in, is engaging in, or is about to engage in any such act, practice, or contract, he may execute in writing and cause to be served upon any person who is believed to have information, documentary material, or physical evidence relevant to the alleged violation, an investigative demand requiring such person to furnish, under oath or otherwise, a report in writing setting forth the relevant facts and circumstances of which he has knowledge, or to appear and testify, or to produce relevant documentary material or physical evidence for examination, at such reasonable time and place as may be stated in the investigative demand, concerning a provision covered under § 53-9-13 or the advertisement, sale, or offering for sale of any merchandise.
SDCL 37-24-12