At 1426 F Street in Downtown Sacramento there's a charming Victorian with a dark history. It's where Dorothea Puente ran a boarding house, taking in elderly and disabled tenants. But in the fall of 1988, Sacramento Police Detective John Cabrera and his team dug up what he called "Dorothea's Graveyard."  Was the grandmotherly woman a serial killer? Investigators were determined to find out.