From the Wikipedia reference section.

Review by J. Doyle Wallis | posted December 17, 2002 | E-mail the Author Reviews for the first two Guinea Pig DVD releases Vol One and Vol 2. The short story is, The Guinea Pig series began on the Japanese home video market in the mid 80's, intended as a series of shorts aimed at the extreme horror fan, so much so that the first volume was a faux snuff film of a woman being tortured. The first two volumes (the second being cruel torture but more cinematic and less raw) were hits and the series quickly completely abandoned the snuff approach and veered to narrative horror tales. While there was some minor controversy in Japan, the series didn't really reach any large acclaim, notorious or otherwise, in America until (I'm assuming a coked out of his brain) Charlie Sheen viewed a bootleg of Flowers... and turned it over to the authorities because he wasn't sure if it was an authentic snuff film (an urban legend- the snuff film market- that has never found even a shred of evidence that it exists in any way). Despite the FBI already being aware of the film(s) and having proven they were indeed hoaxes, the US media jumped on the videos and turned their ever condemning overhyped eye on them and profiled the videos very briefly until some kid probably fell in a well or Hollywood star picked up a transvestite and the media moved on.