|She (1965) [Leo Vincey/Kallikrites]: Stabbed in the stomach by Ursula Andress; shown in a flashback when John's present-day self remembers his previous incarnation's death. His past-self's perfectly preserved body is seen when Ursula shows it to his present-self.
Torso (I Corpi presentano tracce di violenza carnale; The Bodies Bear Traces of Carnal Violence) (1973) [Franz]: Falls over a cliff during a struggle with Luc Merenda; shown from such a distance that we don't know which one was killed until Luc returns to the house.
Nine Guests for a Crime (Nove ospiti per un delitto) (1976) [Lorenzo]: Reportedly killed in an explosion when he tries to start the boat's engine, after the mortally-wounded Dana Ghia sabotages the gas tank. (I haven't seen this movie myself.) (Thanks to Andrea)
Fear (L'Ossessione che uccide; Delirium; Murder Obsession) (1980) [Oliver]: Commits suicide (off-screen) by drinking poison; his body is shown afterwards when Stefano Patrizi discovers him in the basement, along with a tape-recorded "suicide note."