22. Chester Nut

Chase and August arrive at the scene of a murder at a mental hospital, where a prominent psychiatrist has been stabbed to death. The suspect is a patient, Treat Donnelly, who is revealed to be Chase's cousin and vehemently denies killing the doctor. Several of Dr. Benning's colleagues fall under suspicion, and the plot thickens when it is learned that Elaine Hall, the dead doctor's beautiful assistant and one of the suspects, has more than one personality.