Snuff movie
A snuff film is a film, sometimes pornographic, that supposedly depicts the actual murder of a human.There has been no documented example of any snuff film ever being distributed. The existence of snuff films appears to be an urban legend.
The idea of snuff films comes from the movie Snuff, the ending of which shows the faked murder of a crew member.
Sometimes murderers film their crimes; the resultant movies are not considered snuff films because they are not meant for distribution.
The film Hardcore involves a runaway's father investigating the veracity of an 8mm film that appears to be of a teenage girl being murdered. 8mm is a similar movie about a private investigator of this genre of filmmaking.
