A forced disappearance occurs when an organization forces a person to vanish from public view, either by murder or by simple sequestration. The victim is first kidnapped, then illegally detained in concentration camps, often tortured, and finally executed and the corpse hidden. In Spanish and Portuguese, "disappeared people" are called desaparecidos, a term which specifically refers to the mostly South American victims of state terrorism during the 1970s and the 1980s, in particular concerning Operation Condor.

According to the Rome Statute of the International Criminal Court, which entered into force on July 1, 2002, when committed as part of a widespread or systematic attack directed against any civilian population, "forced disappearances" qualify as a crime against humanity, which thus cannot be subject to statute of limitation.

Typically, a murder will be surreptitious, with the body disposed of in such a way as to never be found. The person apparently vanishes. The party committing the murder has deniability, as there is no body to show that the victim is actually dead. Furthermore, the perpetrators of disappearance often go to great lengths to obscure or eliminate all mention of the disappeared, by altering the historical record and encouraging the silence of surviving relatives. In Chile and Argentina, for example, the infamous "death flights" were used during Operation Condor by the military juntas to dispose of the victims' bodies at sea. Since the bodies couldn't be found decades later, those responsible for human right violations claimed that the statute of limitations impeded any trial. However, in Chile, judge Juan Guzmán Tapia would create, by jurisprudence, the felony of "permanent sequestration": he argued that since the bodies couldn't be found, the statute of limitations couldn't be applied since the sequestration continued and was still in effect. Juan Guzmán thus ensured the possibility of bringing to trial some of the Chilean military men involved, even though the amnesty law of 1978 continues to apply, since the democratic government has not yet abrogated it.

Linguistic considerations

In the case of forced disappearance the word disappear, which is properly an intransitive verb, becomes transitive. Victims, who are those who have disappeared, or the disappeared, are said to have been disappeared, rather than the more usual have disappeared. The perpetrators have disappeared them, rather than made them disappear. Of course in these circumstances both the formal expressions "was made to disappear" or "was caused to disappear" and the informal transitive usage are euphemisms: these people have presumably been tortured and murdered; they have indeed disappeared, but forever.

Similar considerations apply in Spanish. Instead of (él) desapareció (he disappeared), we have (ellos) lo desaparecieron (they disappeared him).