Sec. 2. DEFINITIONS. In this Act:

(1) "Penal institution" means a jail, prison, penitentiary, house of correction, or other place of penal detention.

(2) "State" means a state of the United States, the District of Columbia, the Commonwealth of Puerto Rico, and any territory of the United States.

(3) "Witness" means a person who is confined in a penal institution in a state and whose testimony is desired in another state in a criminal proceeding or investigation by a grand jury or in any criminal action before a court.