mail threat

A mail threat is a threat communicated in writing through the postal system — most often a letter with seriously threatening content directed at a specific person or institution. The concept belongs to international and in particular US federal law; it is not part of Danish law, and it appears mainly in connection with US federal criminal cases, where sending such threats constitutes a separate offence.

Under US federal law it is punishable to knowingly send, or cause to be sent, a communication containing a threat to kidnap or injure a person. The provision applies whether the letter contains only words or also a dangerous substance, and regardless of whether it ever reaches the addressee. What matters is the intent to threaten and the use of the postal system as the channel.

In a true crime context — including cases involving ricin letters sent to US presidents — the term is used about letters that combine a direct threat with biologically hazardous content. Here the letter functions simultaneously as a mail threat and as a potential means of biological attack, which aggravates the basis for prosecution and brings additional federal provisions on weapons of mass destruction into play.

Conceptually, a mail threat differs from ordinary harassing mail through the requirement of a concrete threatening message. It is the threatening character of the communication — not the physical contents alone — that defines the offence. Intimidation and extortion are typical motives, but the law does not require that a specific demand be made.

In the United States, mail threat cases are typically investigated by the FBI and the United States Postal Inspection Service, which has particular jurisdiction over crimes committed through the US postal system. The sentencing range varies depending on the nature of the threat and any accompanying circumstances.