Mental health professionals are at high risk for violence, even murder, by their psychotic clients. Psychotic perpetrators also commit mass murders of unknowns as well as killing their family and friends. These perpetrators differ from non-psychotic murderers, killing innocent strangers in volume, seemingly at random; act alone; attack during daylight; remain, often suiciding on site; are not intoxicated, radicalized, or gang members; give prior warnings of their plans; have prior psychiatric contact; sometimes prior successes, even exceptional; and are motivated by paranoid, grandiose, delusional logic. Non-organic psychoses are caused by severe Bipolar Disorders. Details from the media show that psychotic murderers suffer with severe mania or depression. The current paper presents an epidemiology of such murders and exemplary cases to support this contention that a psychotic Bipolar Disorder is responsible. Prior mental health attention typically produces misdiagnoses of Schizophrenia. Correct diagnosis results in more effective pharmacologic treatment and, potentially, prevention.