Section 14National Internal Revenue Code of 1997 (Republic Act No. 8424), Sec. 14

Authority of Officers to Administer Oaths and Take Testimony. - The Commissioner, Deputy Commissioners, Service Chiefs, Assistant Service Chiefs, Revenue Regional Directors, Assistant Revenue Regional Directors, Chiefs and Assistant Chiefs of Divisions, Revenue District Officers, special deputies of the Commissioner, internal revenue officers and any other employee of the Bureau thereunto especially deputized by the Commissioner shall have the power to administer oaths and to take testimony in any official matter or investigation conducted by them regarding matters within the jurisdiction of the Bureau.