Eight short case histories were presented of patients admitted to Matteawan State Hospital for the Criminal Insane charged or indicted with murder, first degree, occurring as a reaction to paranoid delusions of an involutional psychosis. In all of these cases, forebodings of the malignant nature of patient's mental illness were present. This would indicate that these patients harbored potential homicidal tendencies for a prolonged period of time. A patient in the involutional period with potential homicidal tendencies as a reaction to paranoid delusions, should be hospitalized as a preventive measure as early as possible, the same as is done with potential suicidal patients.Abstract Teaser