California Code, Code of Civil Procedure - CCP § 512.090

(a) The plaintiff may apply ex parte in writing to the court in which the action was brought for an endorsement on the writ directing the levying officer to seize the property at a private place not specified in the writ.

(b) The court shall make the endorsement if the plaintiff establishes by affidavit that there is probable cause to believe that the property or some part of it may be found at that place.