Pennsylvania Statutes Title 16 P.S. Counties § 1404. Filling of vacancies

(a) If any vacancy shall occur in the office of district attorney in a county of the second class A or third class, either by death, resignation, removal from office or from the county, or otherwise, the judges of the court of common pleas shall supply such vacancy by the appointment of a competent person to fill the office during the balance of the unexpired term.

(b) If any vacancy shall occur in the office of district attorney in a county of the fourth through eighth class, the first assistant district attorney shall become district attorney and discharge the duties of the district attorney until the first Monday in January following the next municipal election occurring not less than ninety days after the occurrence of the vacancy.  If the first assistant district attorney is unwilling or unable to serve, the judges of the court of common pleas shall fill the vacancy by the appointment of a competent person to fill the office until the first Monday in January following the next municipal election occurring not less than ninety days after the occurrence of the vacancy.