Factual error: While using the phone in his cell, Dr. Lecktor asks an operator to dial a Maryland area code, but is then connected to the University of Chicago. (00:30:10)
Factual error: Right before Frank humiliates Dorothy for the first time, he blows out one of the gaslights in her apartment. That is never done in real life, for the same reason you would not blow out the pilot in your stove.
Factual error: Towards the last scene, Howell and Hauer share the same shotgun (Ryder to take pop shots at Jim in the jeep, Jim to ultimately fire three shots to kill Ryder). The shotgun used can hold at most seven or eight shells, not the 12 or more that are fired between Ryder and Jim starting from when Ryder escaped the bus.
Factual error: Throughout the film, they play one of Strauss' Four Last Songs, which is credited as being "September." The song actually played is "Beim Schlafengehn."
Factual error: During the speedboat chase scene, the Toronto skyline is visible, including the CN Tower. This movie is supposed to take place in an American city.
Factual error: Barbara befriends her kidnappers in her joy over losing 20 pounds while she was with them. Leaving aside that she's been with them no more than two weeks, and it's near impossible to lose 20 pounds in that short amount of time even if you literally starved yourself; she also most definitely would have noticed a weight loss that big. On a frame as small as hers, she would have noticed big differences in her body's shape and feel, and none of her clothes would have fit. (01:00:00)
Factual error: Murphy shouldn't even be in charge of escorting Arabella to the bathroom and booking her. Female police officers are put in charge of female prisoners.
Factual error: Ted Bundy is trying to pick up a potential victim in front of a record store, where a poster of Stevie Nicks' album, Rock a Little, is displayed. This scene took place in the mid-1970's, but Nicks' album was released in 1985.