The crime of mail fraud is the use of the mails in furtherance of a scheme to defraud. Without the use of the mails, no matter how large or serious the fraud, there is no federal jurisdiction under this statute. The mailing does not itself need to contain the false and fraudulent representations, nor does it have to be essential to the success of the scheme. The mailing does not even have to actually further the fraud. It is sufficient if the mailing is incidental to an integral or essential part of the scheme, although what is integral or incidental can depend on the facts of each case.

Frauds and swindles are not defined in the mail fraud statute or elsewhere in the U.S. Code. Most of the cases treat any intentional scheme to deceive or deprive another of money, property, or any other valuable right or interest by fraud or false pretenses as being within the statute.

The crime is complete upon using, or causing the use, of the mails in furtherance of the fraud. It is not necessary that the fraudulent scheme succeed or that the victim suffer a loss. It also is not necessary that the predicate mailing travel in interstate commerce; any use of the U.S. postal system provides sufficient grounds for federal jurisdiction.

Reference: Fundamentals of Computer Fraud. (1999). Association of Certified Fraud Examiners.