Investigation Discovery's true-crime series, "Home Sweet Homicide," explores murders committed in the sanctuary of victims' homes. Homeowners are suffused with a sense of safety after locking their doors, enabling their home security systems and turning on all their lights. However, cold-blooded killers violate this sense of safety, using it against their victims, who are taken unawares in the one place where they felt free from danger. Planning the perfect crime, home invaders become acquainted with their targets' routines and familiarize themselves with the layouts of their houses. In one episode, a young mother is found brutally murdered in her home in Chestnut Ridge, N.Y., and detectives scratch their heads over snowy footprints that lead up to her house but not away from it. In another, a top real estate agent vanishes after meeting a new client, and police must find out if anyone had a reason to harm her.