For purposes of this chapter persons found to be both dangerous and mentally ill shall mean persons found by a court of competent jurisdiction pursuant to any lawful proceeding:
(1) To be in such mental condition that they are in need of supervision, evaluation, treatment and care; and
(2) To present a substantial risk of physical harm to other persons as manifested by evidence of homicidal or other violent behavior or evidence that others are placed in reasonable fear of violent behavior and serious physical harm to them; and
(3) To be dangerous to such a degree that a maximum security treatment setting is required.