Continuity mistake: In the scene where Vicki introduces herself to Knox at Gotham Globe, the newspaper she's reading changes between shots. (00:13:25)
Continuity mistake: In the scene where the joker fires at Batman using his extra long gun, the barrel is straight and solid, yet when he is forcing Vicki up the Cathedral steps, he collapses the gun into a pistol.
Continuity mistake: When Knox and Vicki talk about Corto Maltese, she puts her left hand by her neck. Shot changes, and now both hands are on her neck. (00:13:51)
Continuity mistake: Notice The Joker's chin in the bell tower. It's covered in blood when first shown, a shot later it's suddenly just the center of his chin.
Continuity mistake: While Vicky is talking with Bruce at the Batcave she has some tears on her face which disappear between shots.
Continuity mistake: When the Joker is giving the money to the people a bill sticks on the top side of the throne which disappears and reappears between shots.
Continuity mistake: When Mayor Borg urges Harvey Dent to do something about the Joker's Smylex scare, a phone rings. As Dent goes to answer it, the cigar in his right hand jumps to his mouth between frames. (00:58:25)
Continuity mistake: When Nic is dangling helplessly above the back alley, Batman changes position on the building's ledge from one shot to the next (note the seam between his boots). (00:06:30)
Continuity mistake: Right before the Batmobile is forced to park in front of a tractor's plow, it drives down the same stretch of road twice in consecutive shots (note the swerving car). (01:08:35)
Continuity mistake: At the beginning when both muggers are about to be jumped by Batman, one of them lights a cigarette and reassures his buddy that there's nothing to be afraid of. But while he's talking, the load of cash in his right hand vanishes between shots. (00:05:25)
Continuity mistake: At Gotham Globe when Vicki and Knox are talking about wildlife at the desk, Vicki's black shirt conceals her wristwatch between shots. (00:13:50)
Continuity mistake: When Knox walks into Gotham Globe and gets mocked about his recent Batman article, a co-worker hands him a funny Batman drawing just to rub it in. But watch as a coffee cup on the worker's desk turns itself completely around between shots. (00:13:10)
Continuity mistake: Before and after his transformation, the Joker a.k.a. Jack Napier, has brown eyes, but in the flashback, he has blue eyes.
Continuity mistake: When the man is knocked out in the alley he changes positions between shots.
Continuity mistake: While Bruce is talking with Vicky at the Batcave he is clean shaven, but after he attacks Axis chemicals he has some stubble on his face.
Continuity mistake: In the scene where Joker smashes a mirror on the surgical instrument table, a large fragment breaks off and hits the floor. That fragment somehow appears on the tabletop seconds later. (00:35:10)
Continuity mistake: When Knox takes the funny Batman sketch from his co-worker, his right hand jumps to a different part of the paper between frames. (00:13:10)
Continuity mistake: During the Batmobile car chase scene, Batman bangs a left from the side street near Monarch Theatre, leading Joker's henchmen and several patrol cars on a straight path for a few seconds. But right before the car pileup in front of Monarch Theatre, Batman is seen turning left onto the very same side street he came from to begin with. (01:08:00)
Continuity mistake: In the scene where Joker is admiring a black and white photo of Vicki, watch as the crayons in his pink bucket on the table keep changing between shots. (00:53:05)
Answer: He was suspicious, but when she first entered the penthouse and Grissom said to leave their business meeting, he noticed the sexy facial exchange Alicia and Jack gave each other.