Whenever someone disappears, it can never be ruled out that they might have left of their own volition. Except when the disappearance involves an 11-month-old infant. Lisa Irwin has been missing since Oct. 3, 2011, when she was last seen asleep in her crib. Irwin's parents have been suspected of foul play, especially after cadaver dogs indicated a "positive hit" for the scent of a deceased human in the Irwin home, but they have not been charged. Other witnesses say they saw a strange man in the vicinity of the Irwin home carrying a baby with no coat that morning.