The Witness Vanishes (1939)

"WHO WILL BE THE NEXT VICTIM OF THE DREADED MANIAC!"

In this mystery, a newspaper executive and three of his colleagues conspire to have the owner of the highly-respected London Sun committed to an insane asylum. The hapless publisher manages to escape. Soon after, the four collaborators begin dying one-by-one. Oddly their obituaries appear in a rival publication before they are actually killed.