As used in this subchapter:
(1) “Witness” means a person who is confined in a penal institution in any state and whose testimony is desired in another state in any criminal proceeding or investigation by a grand jury or in any criminal action before a court;
(2) “Penal institutions” includes a jail, prison, penitentiary, house of correction, or other place of penal detention;
(3) “State” includes any state of the United States, the District of Columbia, the Commonwealth of Puerto Rico, and any territory of the United States.