Mailing Threatening Communications 18 U.S.C. Sec. 876 is a federal law that prohibits the sending of any communication, by any means, containing a threat to injure the person of another. This law applies to any type of communication, including mail, email, text messages, and social media posts. Under this law, there are two types of mailing threatening communications: 1. Direct Threatening Communications: This type of communication contains an explicit threat to injure the person of another. 2. Implicit Threatening Communications: This type of communication has a veiled or implied threat of harm, which could be interpreted as a threat by a reasonable person.