They Only Kill Their Masters 1972

Abel Marsh, the police chief of the sleepy California coast town of Eden Landing, returns from vacation to the shocking news that divorcée Jenny Campbell has been killed by her pet Doberman, Murphy, on the shore of her beachfront home.

He visits Dr. Warren G. Watkins, the veterinarian who tranquilized the dog when it was found beside Jenny’s body, and meets Watkins’ new nurse, Kate Bingham, who objects to euthanizing Murphy. She demonstrates how the dog obeys voice commands and quietly notes a chilling detail: dogs typically attack the throat. This raises a troubling question for Abel as he wonders why Jenny’s injuries were found on her extremities instead of the neck, prompting him to order an autopsy. The pathologist reveals Jenny drowned in freshwater laced with salt and, devastatingly, that she was pregnant. It becomes clear that Murphy did not kill Jenny; rather, the dog likely dragged her body from the sea after she had already died.

Abel presses Jenny’s ex-husband, the wealthy playboy Lee Campbell, who admits their marriage ended because she fell in love with another woman. Abel and Kate return to the dead woman’s house under the guise of a routine search, and Kate—who has begun to soften toward Abel—confirms that the bathtub had been cleaned with industrial disinfectant, suggesting a deliberate attempt to stage evidence. The investigation deepens as Abel, now personally connected to Murphy, takes the dog in and forms a bond with him. The pair’s growing rapport mirrors Abel’s evolving relationship with Kate, and the two share a night together, complicating the professional boundaries of the case.

Captain Daniel Streeter, Abel’s long-time ally and head sheriff, questions how Abel is handling the case but supports him staying in charge. Abel proceeds to the Campbell residence to interview Lee Campbell again, only to discover the home ablaze and Campbell dead from stab wounds, the fire reportedly slowed by a sports car blocking the tunnel. The night’s events push Abel to consider every possible suspect, including those closest to the victim.

Back at Abel’s home, the mystery deepens as he ponders why Murphy did not bark during the critical moments. A subtle test—tapping the dog’s snout—triggers Murphy into attack mode, underscoring that someone had inadvertently or purposely set the dog off. Abel returns Murphy to Watkins, but the tension escalates when Kate reveals she knows the dog’s name because Watkins told her. Realizing that Watkins has known Murphy for a long time, Abel makes a decisive move and arrests the veterinarian. Watkins fights back by injecting Abel with an animal euthanasia drug, and Abel manages to call for help before he collapses.

Awakening in the hospital, Abel learns from Streeter that the drug has been flushed from his system and that Watkins has managed to evade capture. The next day, Abel tracks the doctor down, who insists he did not kill anyone. As they head downstairs, Mrs. Watkins strikes Abel from behind; Watkins darts outside where he is shot by Streeter. With Watkins dead, Mrs. Watkins reveals a devastating truth: she had been Jenny’s lover, but when Jenny also pursued the doctor, she killed Jenny and Lee Campbell, and her husband helped cover up both crimes.

This layered unraveling exposes the tangled loyalties and hidden desires that drove the town’s darkest acts, leaving Abel to reconcile trust, betrayal, and justice in a case that started with a dog and ended with a deadly web of passion and concealment.