Assassinated, some would say. Here is a rather wonderful song by Coil on the subject
As it happens, I quite like Salo. The BFI blu ray I have of it I would recommend to mostly anyone, it looks incredible, and features a bunch of documentarys about the movie and director that help with the (as pointed out above) 'why'.
Yeh, just read it's meant to be based on a book by Marquis De Sade who's name the word sadism comes from (T think?) so that gives people an idea,
The whole film has been posted on Youtube by several users, if anybody wants to try it, you have to sign in, of course.