Using the Future Perfect Tense

Usually, as in English, the future perfect tense of Spanish refers to an action of some sort that will be completed at a future time. An example is a sentence such as "habrá vuelto para lunes" (she will have returned by Monday). But in Spanish, despite its name, the future perfect tense can also be be used to refer to something that has probably already happened. It's a special usage of the "suppositional future," the use in Spanish of the future tense to refer to probability.