The Terror with Cross-Eyes(1972)

To gain fame quickly - three actors - Mino, Giacinto and Mirella, stage a fake murder (Mirella is the "victim"), then plan to find the "body" at the most opportune moment. Unfortunately, a real murder takes place in Mirella's apartment when a young woman named Margaret is killed. Having left abundant clues to the fake murder, Mino and Giacinto realise the only way to save themselves from jail is to find Margaret's killer. Despite the intrusions of a stupid police inspector, the two men discover she was killed by a mysterious "organization". Although every witness they try to question is killed by a hitman, they eventually unravel the mystery...