As the two Secret Service men are running past the front gate after the kidnapping, the bar on the gate has been lowered and they run around it. In the video tapes of the same scene that Cross reviews, the two men run straight out into the street, and there is no bar blocking their path.
When Soneji returns from his firefight with Cross and Flannigan outside the Russian President's house, he has a silencer on his gun, but during the firefight he clearly doesn't have one on.
When Alex Cross breaks into Jezzie Flanagan's apartment, he is shown turning on her computer. But the monitor is already on and showing a blue screen before he reaches the desk where the computer is located.
Just before Cross meets with the Senator and his wife, and plays them the phone conversation, Cross, Flannigan and McArthur discuss Flannigan's involvement in the case. Flannigan is asked how long she has been assigned at the school (Cathedral), and replies 2 years. Later on, in Flannigan's apartment, she tells cross she didn't want the assignment at the school, but has been responsible for Megan for the 3 years she has been there.
The teacher talks about Charles A. Lindbergh. He turns to the blackboard and writes at or just above his eye level. Yet when the camera views his face from the blackboard, he is writing at or below his shoulder height.
The U.S. Secret Service does not protect Senators and their families. The Secret Service protects the Presidents, Vice-Presidents, former Presidents, Presidential candidates, Spouses and/or young children of a sitting President and visiting heads of state.
At the beginning of the movie, the driver of the corvette slams on the brakes, causing the passenger to hit her head on the dashboard. When the car is hanging from the guardrail moments later, she is clearly wearing her seat belt. If she had her seat belt on when the driver hit the brakes, her head would not have hit the dash, as the seat belt has a locking mechanism.
When the Russian security team runs outside to investigate the gun shots at the Embassy, they leave the grounds, thus violating the area within which they have authority. Once back on American soil, like the sidewalk by the phone booth, they have no jurisdiction.
Dr. Alex Cross goes back to Jezzie's apartment to investigate his suspicions of her, and when looking around her apartment, the rifle used to kill Soneji is still there. Although the rifle is in an evidence bag, the weapon would have not have been left there. It would have been taken by the police as evidence.
While going through the files on the computer at Megan's desk, Agent Hickley describes GIFs to Dr. Cross as being made up of billions of ones and zeros. In fact, even just one billion binary bits (ones and zeros) would be over 100 megabytes - at least a hundred times the size of typical GIF images.
In one of the news broadcasts Megan is described as twelve years old, weighing fifty two pounds and measuring three feet and five inches tall. She is clearly much taller than this and almost certainly weighs more. Those measurements would be about right for an average six or seven year old girl.
When Jezzie is trying to get Megan out of the room in the barn and she shoots through the door of the room, she shoots at least 20 times with a pistol that, if a trivia entry identifying it as a S&W 3913 is taken as fact, holds only 9 rounds.
When Sonji strangles the woman in the office, she is supposed to be dead but when they show her she is blinking.
After just killing Ben, Jezzie leaves house to check on and to essentially execute Megan, who is held hostage in the barn. With the adrenaline still coursing through her veins, she momentarily loses her cool and starts emptying her gun into the wooden planks of the room where Megan is held up. The first clip of shots come from a black pistol, after Jezzie reloads, it's a chrome pistol.
The Turkish shotgun makes the sound of a pump-action shotgun, despite the fact that it is a double-barreled, break-action gun.
When Cross enters Union Station, the caller tells him to get on "the Metro", which is the common term for the Washington DC subway system. A few scenes later, a news reporter refers incorrectly to the subway system as "the MTA". The term "MTA" is used by metros in other American cities, including Baltimore where this scene was filmed.
When Cross and Flannigan arrive at Chesapeake Bay to investigate the scene of the murdered fisherman, mountains are visible in the background. There are no mountains at all in that region.
The kidnapper tells Cross to run from the Watergate to 6th and Pennsylvania Avenue in 14 minutes, a distance of 2.1 miles. Then the kidnapper instructs him to double-back to 12th and Madison in 12 minutes (another .6 miles). The pay phone at 12th and Madison does not exist, that address is in the middle of the National Mall. The kidnapper then instructs Cross to get to Union Station in 4 minutes which is another 1.5 miles. First, that last leg of the run is ridiculous. Secondly, that is a total of 4.2 miles of running 30 minutes-not a bad workout in a full suit, trench coat, and dress shoes.
Going to the school, Cross heads west into Virginia from the Lincoln Memorial. Coming back, he also heads west along Pennsylvania Avenue (with the Capitol dome in the background), which is east of the Lincoln Memorial.
At one point, we see Alex drive past a Save-On-Foods supermarket. (You can tell by its trademark neon lights.) However, Save-On-Foods only have stores in the Canadian provinces of British Columbia and Alberta.
Dr. Cross refers to the executed kidnapper of the Lindbergh baby as "Richard Bruno Hauptmann". The kidnapper's name was actually "Bruno Richard Hauptmann".
Anna Maria Horsford played May Cross the mother of the kidnapped Naomi in "Kiss the Girls". She returns for "Along Came a Spider", but she's playing Alex's wife Vickie Cross. It was very unusual.