16 Pa. Stat. § 1406
If any district attorney is charged, according to law, with any crime or misdemeanor, before or bound over or committed by any court to answer for willful and gross negligence in the execution of the duties of the office, it shall be the duty of the court to appoint a competent attorney thereof to prepare an indictment against such district attorney and to prosecute the same on behalf of the Commonwealth until final judgment. The attorney shall be paid by the county for services a reasonable compensation to be fixed by the court. If the district attorney is convicted of any crime for which that individual may be sentenced to imprisonment by separate or solitary confinement at labor, the office shall be declared vacant by the court.
16 P.S. § 1406