Welf. & Inst. Code, § 604

(a) Whenever a case is before any court upon an accusatory pleading and it is suggested or appears to the judge before whom the person is brought that the person charged was, at the date the offense is alleged to have been committed, under the age of 18 years, the judge shall immediately suspend all proceedings against the person on the charge. The judge shall examine into the age of the person, and if, from the examination, it appears to the judge’s satisfaction that the person was at the date the offense is alleged to have been committed under the age of 18 years, the judge shall immediately certify all of the following to the juvenile court of the county:

(1) That the person (naming the person) is charged with a crime (briefly stating its nature).

(2) That the person appears to have been under the age of 18 years at the date the offense is alleged to have been committed, giving the date of birth of the person when known.

(3) That proceedings have been suspended against the person on the charge by reason of the person’s age, with the date of the suspension.

The judge shall attach a copy of the accusatory pleading to the certification.

(b) When a court certifies a case to the juvenile court pursuant to subdivision (a), it shall be deemed that jeopardy has not attached by reason of the proceedings prior to certification, but the court may not resume proceedings in the case, nor may a new proceeding under the general law be commenced in any court with respect to the same matter unless the juvenile court has found that the minor is not a fit subject for consideration under the juvenile court law and has ordered that proceedings under the general law resume or be commenced.

(c) The certification and accusatory pleading shall be promptly transmitted to the clerk of the juvenile court. Upon receipt thereof, the clerk of the juvenile court shall immediately notify the probation officer who shall immediately proceed in accordance with Article 16 (commencing with Section 650).

(d) This section does not apply to any minor who may have a complaint filed directly against them in a court of criminal jurisdiction pursuant to Section 707.01.

(e) If the person whose case has been certified to a juvenile court pursuant to this section has their records sealed in juvenile court, the juvenile court shall also order all criminal court records associated with that juvenile record sealed.