The following certificates are necessary to establish that an individual is an eligible person:

(a) Certificates as to nationality. A certificate issued by an authorized official of the Department of State, stating that the individual is a national of the United States.

(b) Certificate as to mental condition. Either (1) a certificate obtained or transmitted by an authorized official of the Department of State that the individual has been legally adjudged insane in a named foreign country; or (2) a certificate of an appropriate authority or person stating that at the time of such certification the individual was in a named foreign country and was in need of care and treatment in a mental hospital. A statement shall, if possible, be incorporated into or attached to the certificate furnished under this paragraph setting forth all available medical and other pertinent information concerning the individual.

(c) Appropriate authority or person. For the purpose of paragraph (b)(2) of this section a medical officer of the Public Health Service or of another agency of the United States, or a medical practitioner legally authorized to provide care or treatment of mentally ill persons in the foreign country, is an “appropriate authority or person,” and shall be so identified in his execution of the certificate. If such a medical officer or practitioner is unavailable, an authorized official of the Department of State may serve as an “appropriate authority or person,” and shall, in the execution of the certificate, identify himself as serving as such person due to the unavailability of a suitable medical officer or practitioner.