Secret of the Whistler
Ralph Harrison (Richard Dix) is married to Edith (Mary Currier), a rich woman who has been suffering heart attacks. Upset by her condition, he finds consoling companionship with an artist’s model, the unscrupulous gold-digger Kay (Leslie Brooks).
He falls in love with Kay. Edith's health then improves. Edith overhears Ralph professing his love for Kay. Edith threatens Ralph, saying she’s going to take him out of her will. He decides to poison her, with her own medicine, before she can meet with her lawyers.
After Edith dies, Ralph marries Kay, who becomes suspicious of how Edith died and worried for her own fate. Finding incriminating diary pages and the medicine, she has the medicine analyzed, discovering that it was poisoned.
Ralph overhears the phone conversation with the lab. Pretending to embrace her, he strangles Kay to death, just as the police arrive and arrest him for murder — a murder he didn’t need to commit because Edith hadn’t taken the poisoned medicine after all, but died of a heart attack, before she could take it.
murder