Human remains dogs are distinct from the dogs that search for escaped felons and the dogs that search for whole cadavers. They are trained to alert their owners when they detect the specific scents of decomposed human tissue. They can pinpoint the location of a corpse at the bottom of a lake by sniffing the water's surface for the gases and fats that float up from the rotting remains. They can detect the lingering scent molecules of a decomposing body up to fourteen months after the killer lugged it away.