Art. 11.37. DEATH, ETC., SUFFICIENT RETURN OF WRIT.  It is a sufficient return of the writ of habeas corpus that the person, once detained, has died or escaped, or that by some superior force he has been taken from the custody of the person making the return;  but where any such cause shall be assigned, the court or judge shall proceed to hear testimony;  and the facts stated in the return shall be proved by satisfactory evidence.
Acts 1965, 59th Leg., vol. 2, p. 317, ch. 722.