Wash. Rev. Code § 19.09.410
For the purpose of any investigation or proceeding under this chapter, the attorney general or any officer designated by the attorney general may administer oaths and affirmations, subpoena witnesses, compel their attendance, take evidence, and require the production of any books, papers, correspondence, memoranda, agreements, or other documents or records which the attorney general deems relevant or material to the inquiry.
In case of willful failure on the part of a person to comply with a subpoena lawfully issued by the attorney general or on the refusal of a witness to testify to matters regarding which the witness may be lawfully interrogated, the superior court of a county, on application of the attorney general and after satisfactory evidence of willful disobedience, may compel obedience by proceedings for contempt, as in the case of disobedience of a subpoena issued from the court or a refusal to testify therein.
RCW 19.09.410