405 ILCS 10/3

A person alleged to be of unsound mind found in this State, who has fled from another state in which, at the time of his flight:

(a) he was under detention by law in a hospital, asylum or other institution for the insane as a person of unsound mind, or

(b) he had been theretofore determined by legal proceedings to be of unsound mind, the finding being unreversed and in full force and effect, and the control of his person having been acquired by a court of competent jurisdiction of the state from which he fled, or

(c) he was subject to detention in such state, being then his legal domicile (personal service of process having been made) based on legal proceedings there pending to have him declared of unsound mind,

shall, on demand of the executive authority of the state from which he fled, be delivered up to be removed thereto.