Red Herrings

A red herring is the name given to a device which intends to divert the audience from the truth or an item of significance. Can work with other devices such as enigmas to create suspense.

For example, in Saw two characters spend time imprisoned in a room in which a third person lies dead. Throughout the film, both characters appear to be guilty of a series of murders, until it is discovered at the end that the third person in the room is not actually dead, but is, in fact, the killer.