(815 ILCS 505/5) (from Ch. 121 1/2, par. 265)
Sec. 5.
Service by the Attorney General of any notice requiring a person to file a statement or report, or of a subpoena upon any person, shall be made
(a) personally by delivery of a duly executed copy thereof to the person to be served, or if a person is not a natural person, in the manner provided in the Civil Practice Law when a complaint is filed, or
(b) by mailing by certified mail a duly executed copy thereof to the person to be served at his last known abode or principal place of business within this State.
Service of any subpoena issued by a State's Attorney shall be made in the manner provided in the Civil Practice Law.
(Source: P.A. 84-748.)