Welfare and Institutions Code § 681.5

681.5.

If a prosecuting attorney has appeared on behalf of the people of the State of California in any juvenile court hearing which is based upon a petition that alleges that a minor is a person within the description of Section 602, neither that prosecuting attorney nor any attorney from the office of that prosecuting attorney shall represent the minor in a juvenile court proceeding alleging that a minor is a person described in Section 300.