Prosecutors in the case of 17-year-old Michael Mason Jr. of Embden, under indict

Prosecutors in the case of 17-year-old Michael Mason Jr. of Embden, under indictment for the murder of his mother and younger brother, introduced an audio tape on which Mason threatened to kill his mother and brother moments before they were shot to death. The tape was introduced during a hearing on whether Mason should be tried as a juvenile or as an adult