It shall be the duty of the secretary of the department of social and health services, in cooperation with the United States bureau of immigration and/or the United States department of the interior, to arrange for the deportation of all alien sexual psychopaths, psychopathic delinquents, or mentally ill persons who are now confined in, or who may hereafter be committed to, any state hospital for the sexual psychopath, psychopathic delinquent, or the mentally ill in this state; to transport such alien sexual psychopaths, psychopathic delinquents, or mentally ill persons to such point or points as may be designated by the United States bureau of immigration or by the United States department of the interior; and to give written permission for the return of any resident of Washington now or hereafter confined in a hospital for the sexual psychopath, psychopathic delinquent, or the mentally ill in a territory of the United States or in a foreign country. Mentally ill person for the purposes of this section shall be any person defined as mentally ill under RCW
72.23.010, as now or hereafter amended.