Cal. Gov. Code § 68753
In any pending investigation or formal proceeding, the commission or the masters may order the deposition of a person residing within or without the state to be taken in such form and subject to such limitations as may be prescribed in the order. If the judge and counsel for the commission do not stipulate as to the manner of taking the deposition, either the judge or counsel may file in the superior court a petition entitled "In the Matter of Proceeding of Commission on Judicial Performance No. ________ (state number)," and stating generally, without identifying the judge, the nature of the pending matter, the name and residence of the person whose testimony is desired, and, directions, if any, of the commission or masters, asking that an order be made requiring that person to appear and testify before a designated officer. Upon the filing of the petition, the court may make an order requiring that person to appear and testify. A subpoena for the deposition shall be issued by the clerk and the deposition shall be taken and returned, in the manner prescribed by law for depositions in civil actions. If the deposition is that of a person residing or present within this state, the petition shall be filed in the superior court of the county in which the person resides or is present; otherwise in the superior court of any county in which the commission maintains an office.
Ca. Gov. Code § 68753