22 CFR 521.8 - Service of complaint.
(a) Service of a complaint must be made by certified or registered mail or by delivery in any manner authorized by rule 4(d) of the Federal Rules of Civil Procedure. Service is complete upon receipt.
(2) A United States Postal Service return receipt card acknowledging receipt; or
(4) In case of service abroad authenticated in accordance with the Convention on the Service Abroad of Judicial and Extra Judicial Documents in Civil or Commercial Matters.