The Straight Dope: Is There Such a Thing as a Snuff Film? Cecil Adams says in the 30 years stories of snuff films have been circulation, no genuine example has ever come to light. http://www.straightdope.com/classics/a5_258.html
AFU Archive: Faces of Death Review Time-indexed analysis of purported deaths in "Faces of Death", pointing out obvious fakes. Only three sequences in the 100 minute feature are considered to be probably genuine. http://www.urbanlegends.com/movies/faces_of_death_review.html