The Police Are Blundering in the Dark Movie

Original title: La polizia brancola nel buio

A woman is stabbed by an unidentified person wielding a pair of scissors when her car breaks down on a deserted road. The rest of the "action" of the film takes place in a house where the same killer starts knockin' off most of the chicks that are staying there. There seems to be some sort of side plot about a paralyzed guy who fidgets with some sort of mechanical gadget in a secret room that may or may not control a mask with a flashing eye in the dining area that may or may not exhibit some sort of mind-control over guests at the house... themoviedb