25 U.S.C. § 36 : US Code - Section 36: Special agents and other officers to administer oaths

Search 25 U.S.C. § 36 : US Code - Section 36: Special agents and other officers to administer oaths

Each special agent, supervisor of schools, or other official
charged with the investigation of Indian agencies and schools, in
the pursuit of his official duties shall have power to administer
oaths and to examine on oath all officers and persons employed in
the Indian Service, and all such other persons as may be deemed
necessary and proper.