28 C.F.R. § 71.8 Service of complaint.
Title 28 - Judicial Administration
(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. (b) Proof of service, stating the name and address of the person on whom the complaint was served, and the manner and date of service, may be made by (1) Affidavit of the individual serving the complaint by delivery; (2) A United States Postal Service return receipt card acknowledging receipt; or (3) Written acknowledgment of receipt by the defendant or his or her representative.
Title 28: Judicial Administration
PART 71—IMPLEMENTATION OF THE PROVISIONS OF THE PROGRAM FRAUD CIVIL REMEDIES ACT OF 1986
Subpart A—Implementation for Actions Initiated by the Department of Justice
§ 71.8 Service of complaint.

