18 U.S.C. Sec. 1701 is a federal law that prohibits any individual from obstructing or delaying the passage of mail. It is a crime to knowingly and willfully obstruct or interfere with the delivery of mail, including stealing, tampering, hiding, or destroying mail. There are three types of Obstruction of Mails under this law: Tampering, Theft, and Destruction. Tampering includes any unauthorized alteration, interception, or interference with the mail, while Theft involves any stealing or taking of mail. Lastly, Destruction refers to any malicious destruction or refusal to deliver mail.