Wire fraud and mail fraud go hand in hand. The federal criminal code's prohibition against Mail Fraud is not targeted at unscrupulous junk mail senders, but rather people who use the mail in furtherance of a fraudulent plan or scheme. Nearly every single federal prosecution alleging fraud will charge wire fraud, mail fraud, or both. The statute governing mail fraud at 18 U.S.C. § 1341 is as follows:
Whoever, having devised or intending to devise any scheme or artifice to defraud, or for obtaining money or property by means of false or fraudulent pretenses, representations, or promises, or to sell, dispose of, loan, exchange, alter, give away, distribute, supply, or furnish or procure for unlawful use any counterfeit or spurious coin, obligation, security, or other article, or anything represented to be or intimated or held out to be such counterfeit or spurious article, for the purpose of executing such scheme or artifice or attempting so to do, places in any post office or authorized depository for mail matter, any matter or thing whatever to be sent or delivered by the Postal Service, or deposits or causes to be deposited any matter or thing whatever to be sent or delivered by any private or commercial interstate carrier, or takes or receives therefrom, any such matter or thing, or knowingly causes to be delivered by mail or such carrier according to the direction thereon, or at the place at which it is directed to be delivered by the person to whom it is addressed, any such matter or thing, shall be fined under this title or imprisoned not more than 20 years, or both. If the violation affects a financial institution, such person shall be fined not more than $1,000,000 or imprisoned not more than 30 years, or both.
In order to prevent apprehension, many people use a post office box and an assumed name. When used in conjunction with Mail Fraud, the use of a fictitious name or address is a separate criminal offense under 18 U.S.C. § 1342:
Whoever, for the purpose of conducting, promoting, or carrying on by means of the Postal Service, any scheme or device mentioned in section 1341 of this title or any other unlawful business, uses or assumes, or requests to be addressed by, any fictitious, false, or assumed title, name, or address or name other than his own proper name, or takes or receives from any post office or authorized depository of mail matter, any letter, postal card, package, or other mail matter addressed to any such fictitious, false, or assumed title, name, or address, or name other than his own proper name, shall be fined under this title or imprisoned not more than five years, or both.