California Code, Probate Code - PROB § 8502

(a) The personal representative has wasted, embezzled, mismanaged, or committed a fraud on the estate, or is about to do so.

(b) The personal representative is incapable of properly executing the duties of the office or is otherwise not qualified for appointment as personal representative.

(c) The personal representative has wrongfully neglected the estate, or has long neglected to perform any act as personal representative.

(d) Removal is otherwise necessary for protection of the estate or interested persons.

(e) Any other cause provided by statute.