The Strange Case of Doctor Rx (1942)

Millionaire sportsman Grayson Carter is found strangled to death at the Drexel Club in New York City, and becomes the fifth victim of the mysterious vigilante known as "Dr. Rx," a physician who kills crooks who have been acquitted of murder through various legal maneuvers. The next day, when famed private detective Jerry Church returns to the city after a year in South America, worried police captain Bill Hurd tells him that gangster boss Anthony Zarini has been charged with murder and is being defended by ace lawyer Dudley Crispin. When Hurd suggests that he investigate the case, Jerry tells the captain that he has quit detective work to return to his family's bond business in Boston. Later, John Crispin, Dudley's brother, attempts to hire Jerry for his sibling, and though the detective refuses the job, he agrees to see Dudley that night at his home on Long Island. Anxious to protect his client from retribution, Dudley offers Jerry $10,000 to take the case, with a $10,000 bonus if he finds Dr. Rx. The detective refuses once again, but reconsiders the offer after a female prowler is chased off the property. After leaving the Crispin estate, Jerry finds a note in his car, advising him to see Barney Scott in Syracuse. Immediately upon his acquittal, Zarini becomes the sixth victim