The marquis Galeazzo di Torre Alta is murdered by a mysterious killer who calls himself Diabolicus. His heirs are his three brothers and a sister, but all of them, with the exception of Monsignor Antonino di Torre Alta, are killed by Diabolicus. The police are unable to solve the case, but when Antonino gives his inheritance to Pasquale Bonocore, illegitimate son of his father and Pasquale is in prison and therefore can't be the killer, all the clues are in the hand of the police.
Unfortunately the movie Totò diabolicus is not yet available on HBO Max.
| Directing | Steno | Director |
| Writing | Bruno Corbucci | Screenplay |
| Directing | Mariano Laurenti | First Assistant Director |
| Costume & Make-Up | Sergio Angeloni | Makeup Artist |
| Writing | Roberto Gianviti | Screenplay |
| Sound | Enzo Silvestri | Sound |
| Directing | Renata Clerici | Script Supervisor |
| Camera | Renato Fait | Assistant Camera |
| Writing | Giovanni Grimaldi | Screenplay |
| Production | Gianni Buffardi | Producer |
| Editing | Marcella Bevilacqua | Assistant Editor |
| Writing | Vittorio Metz | Story |
| Writing | Roberto Gianviti | Story |
| Camera | Stelvio Massi | Camera Operator |
| Camera | Enzo Barboni | Director of Photography |
| Writing | Marcello Fondato | Screenplay |
| Art | Giorgio Giovannini | Production Design |
| Writing | Vittorio Metz | Screenplay |
| Editing | Giuliana Attenni | Editor |
| Costume & Make-Up | Giuliano Papi | Costume Design |
| Art | Brunello Serena Ulloa | Set Decoration |
| Costume & Make-Up | Maria Miccinilli | Hairstylist |
| Directing | Mario Castellani | Second Assistant Director |
| Production | Giancarlo Sambucini | Unit Manager |
| Production | Franco Pranteda | Production Secretary |
| Production | Egidio Quarantotto | Unit Manager |
| Sound | Piero Piccioni | Original Music Composer |