Pen. Code, § 4852.12

(a) In a proceeding for the ascertainment and declaration of the fact of rehabilitation under this chapter, the court, upon the filing of the application for petition of rehabilitation, may request from the district attorney an investigation of the residence of the petitioner, the criminal record of the petitioner as shown by the records of the Department of Justice, any representation made to the court by the applicant, the conduct of the petitioner during the period of rehabilitation, including all matters mentioned in Section 4852.11, and any other information the court deems necessary in making its determination. The district attorney shall, upon request of the court, provide the court with a full and complete report of the investigations.

(b) In any proceeding for the ascertainment and declaration of the fact of rehabilitation under this chapter of a person convicted of a crime the accusatory pleading of which has been dismissed pursuant to Section 1203.4, the district attorney, upon request of the court, shall deliver to the court the criminal record of petitioner as shown by the records of the Department of Justice. The district attorney may investigate any representation made to the court by petitioner and may file with the court a report of the investigation including all matters known to the district attorney relating to the conduct of the petitioner, the place and duration of residence of the petitioner during the period of rehabilitation, and all known violations of law committed by the petitioner.