The Patient in Room 18 (1938) on Netflix

Plot summary

Lance O'Leary works as a private investigator, and a case he cannot close leaves him with a nervous breakdown. His doctor orders rest, so he enters a hospital, the same one where Sara Keate, his friend, serves as head nurse. On his first night there, a wealthy patient named Mr. Warren dies in his room, and medicinal radium valued at $100,000 disappears from his chest. The head doctor, Dr. Lethany, is also found dead. Suspicion falls across the staff, since each member appears to have a reason for wanting the crimes. O'Leary draws on the detective stories he has read to investigate, working with Inspector Foley, whose manner is combative.