TIJUANA, Mexico — A smell of death draped the unfinished two-story house on Calle Loma Alta on Tijuana’s eastern side. Neighbors report sometimes hearing screams coming from the abandoned property.Inside, the floor was littered with empty Coca-Cola bottles and dozens of children’s toys and grade school notebooks. Clothes were piled everywhere, and partially burnt mattresses were propped against the door frames, acting as makeshift, sound-absorbing doors closing off several rooms.In one, heavy chains sat atop wooden planks nailed to the floor. Rocks with more chains attached were piled nearby.S…