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, an example of this is source code.

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