Guido Mannari

Details the graphic and shocking, yet undeniably tragic story of Rome's most infamous Caesar, Gaius Germanicus Caligula. (imdb)

A top undercover cop finds and arrests a series of purse snatchers until he discovers an American at the top of an evil ring of thieves. (imdb)

Mentally disturbed spinster Lise experiences a series of bizarre encounters in Rome as she searches for someone to murder her.

Cormack, the lawman most feared by the rugged pioneers at the turn of the century, has a mysterious bond with "Caribou," an outlaw whom he has jailed. When Caribou escapes from prison, he returns to seek revenge, and the tension mounts as kidnap, danger, and the fierce Canadian winter, spice Cormack's dogged pursuit of his cunning enemy over the rugged land.

A group of young desperados is hunted for several years by a determined bank guard (Jack Palance). Both the gang's actions, and their demise in a climactic finale (à la "Bonnie and Clyde") are very graphic and violent. (imdb)

Storia de fratelli e de cortelli (A story of brothers and knives) is a 1973 Italian comedy-drama film written and directed by Mario Amendola (wikipedia)

Follows Caligula as he kills his devious adoptive grandfather and takes control of the decadent Roman Empire, spiralling into depravity, devastation, and madness (imdb.com).