A very famous safecracker is released from prison temporarily to “test” a new type of safe. The break-in fails, and the bandit is taken back to his cell. During the night, he escapes and run to take revenge on the safe resisted him, after he returns to his cell. An unsuspecting professor is accused of the sensational robbery by fortuitous circumstances, and certainly he would end up behind bars if the real safecracker, released in the meantime, not claim the honor of his deed. More on Wikipedia
Watch Il segreto inviolabile (1939) Italian Film
No English subtitle