Although there are bad feelings between Dr. Harrigan and Peter Melady, the founder of the hospital in which Harrigan works, over ownership of the formula for a new anesthesia that can be used on people who do not tolerate ether, Melady specifically requests Harrigan as his surgeon when he needs an operation. Harrigan’s, wife Ina, who is in love with another man, is also a patient in the hospital as is Melady’s daughter Agnes, an old friend of nurse Sally Keating. When Melady’s regular doctor, Dr. Coate, objects to his patient being operated on by another doctor, Harrigan decides to perform the surgery that night rather than wait for the morning. Sally arrives at the operating room to assist in the surgery, but Melady is not there. She institutes a hospital-wide search, finding Harrigan’s dead body in the elevator but no sign of Melady. During the police investigation, several things throw suspicion on Sally, but George Lambert, an intern who is in love with Sally, decides to help clear her. George and Sally find the body of a dead black man in the basement and realize that Melady’s body, rather than the black man’s, was taken to the morgue. An autopsy is performed on Melady’s body after it is determined that he died of fright. When Sally is arrested, George tells the police that he believes that Agnes slipped a vial of anesthesia into Harrigan’s drinking water, making him unconscious. According to George, Melady died of fright when one of the inventors of the drug tried to threaten him. After George poses his theories, Sally is attacked by someone searching for the drug. When her attacker is captured, he is revealed to be Simon, another intern who also worked on the formula. Nurse Lillian Cooper then confesses that she wiped the handle of the murder weapon clean because she knew Simon was the murderer. She hated Harrigan, her former husband, because he divorced her in order to marry a wealthy woman. Dr. Coate apologizes to Sally for his suspicions about her, but she admits that she is leaving the hospital anyway to marry George. More on Wikipedia or Mubi
Watch The Murder of Dr. Harrigan (1936)