Murder Backstage (1960)

Bent on getting her out of the way, a stealthy killer infiltrates the backstage of the Athenian theatre, Gloria, and stabs to death the despised protagonist, Rosa Delli. As the veteran investigator, Inspector Bekas, and his perceptive friend and editor-in-chief, Makris, find the woman lying in a pool of blood, the investigation commences, unravelling long-standing enmities and deep-seated antipathies festering within the walls of the theatre. Indeed, there is more to Gloria's minuscule and not-so-glamorous world than meets the eye, and now, everyone is a suspect--including those with seemingly rock-solid alibis. But, time is running out, and the ruthless assassin is still at large. Murder will out?