NYC Terror Threat a Hoax?

CNN reports that the NYC subway terror threat made last week was a hoax. Apparently the informant in Iraw had admitted that he made the whole thing up. NY mayor Michael Bloomberg and city police officials are not convinced, however, that the threat was a hoax. Bloomberg said that the informant passed a lie detector test. The informant claimed that a baby stroller would be used to carry an explosive device onto a NYC subway.

There's a reason that polygraph tests are not admissable in court; they are scietifically unsound.