Slaughter Hotel (1971)

Sleazy giallo from Fernando Di Leo, originally released in Italy as La bestia uccide a sangue freddo which roughly translates as The Beast Kills in Cold Blood.  It's set in an up-market retreat for rich weirdos and, as you would hope and expect, a masked killer is bumping people off in gruesome fashion.  But who?  And why?  Frankly, the who and the why kind of get lost amid the liberal (and I mean that in every sense) doses of near-pornographic nudity and bloody violence.  It's all wrapped up neatly at the end though.  Cast-wise, Rosalba Neri makes an impression as another in her long line of nymphomaniacs and Klaus Kinski wanders serenely through the movie despite looking less like a psychiatrist than anyone you've ever met.