Many theories have been proposed to help understand delusional misidentification syndromes (DMS) and the danger associated with them. We report on three cases with histories of paranoid schizophrenia who developed DMS. Two of them acted out on delusional thinking toward their sons. Case 1 managed to kill her son and Case 2 was caught twice trying to choke him. Our case reports suggest that the degree of threat perceived by the patient from the delusionally misidentified object is the most important factor in determining the patient's response to the delusions. Alcohol and substance intoxication facilitated the patients' acting out on their delusions, but did not explain the genesis of the delusions. There is a need to continue to study patients with DMS in order to provide opportunity for greater understanding of the psychopathology of DMS.