When Columbo is in Barney's Beanery eating chili and Margaret Williams comes to meet him, they move from the counter to a booth. When they leave the counter, Columbo has stirred his chili, but he has not eaten any. When they get to the booth, Columbo's chili is about half-eaten. Furthermore, Columbo picks up a large portfolio and tucks it under his arm as he leaves the counter, but he seems to have lost it when he gets to the booth.
When Leslie Williams leaves her husband's 1971 Lincoln sedan at the stop sign and goes to a mailbox to mail the ransom note, she is startled by an approaching car. The car is a Corvette. However, as the car is shown driving away, the rear of the car is a 1971 Lincoln sedan.
When Leslie brings the plane to a halt after her flight with Columbo, the plane has nothing behind it. However, the filming of the two characters getting out of the plane was not done as a continual shot (obviously because Peter Falk and Lee Grant were not aboard), and so there immediately materializes a building directly behind the plane as they get out (because the plane was moved to another location for the actor and actress to film the scene).
When Columbo and Mrs. Williams are ordering drinks at the airport bar, a Boeing 747 can be seen taxiing toward them in the background. In the time it takes for Columbo to say "I'll have a Root Beer", the plane vanishes. 20 seconds later, the same plane is taxiing farther into its parking space.
When Columbo talks with Margaret Williams in the restaurant, his shirt collar is sometimes rumpled and sometimes not.
When the injured plaintiff is being examined on the witness stand, he is asked by his attorney about his injuries, and he replies that he injured his back. Leslie Williams objects on grounds that this is expert testimony that can only be given by a medical expert and the judge sustains the objection. This is incorrect. A person can testify as to what part of his body he injured and where he feels pain. If the question asked was a technical one, such as what specific disc was injured, that question could be answered only by a medical expert.
Columbo says the victim was shot at a 45-degree angle, proving he was standing up and his killer was sitting down. But the victim could have been lying down and the killer standing, which could also account for the 45-degree angle.
A simple examination of Mr. Williams' body by a medical examiner would have revealed that he had died long before Mrs. Williams got that phone call from her, yet this wasn't done.
On the way to the drop-off for the ransom, Leslie Williams' new heading is 20 degrees Northwest, which is impossible. A 20 degree heading would be North Northeast.
After Leslie Williams completes her "drop" of the ransom, she has a radio communication with the FBI and concludes it by saying, "over and out", which is an oxymoron in radio communications. "Over" means the person is expecting a response back, whereas "Out" means the conversation is finished and there will be no further conversation; it is not correct to use the two terms together.
The stamp on the delivered ransom letter has no cancellation mark. However, it is not unheard of to receive a letter that has not been canceled.
When Leslie Williams gets the fake call saying her husband has been kidnapped, the FBI could have checked with the phone company to find out the incoming phone number.
When Leslie dials her friend Pat, asking her to call her tomorrow to remind her of their tennis date, she only pushes 6 buttons on her touch tone telephone. However, if the number you're dialing is in the same exchange area, the first number can be omitted.
When the tape of Paul telling Leslie the kidnapper's demands finishes, the "click" sound of the phone being hung up is heard; however, it can be see that the film is frozen, thereby making it impossible to hear the click of the phone.
The FBI is in the home awaiting contact from kidnappers, yet when the doorbell rings, they allow her to answer the door by herself, instead of going with her just in case it's a kidnapper or go-between delivering a message.
When Leslie Williams made out the ransom note, she did so with bare hands. Therefore, the authorities would have found her fingerprints on the note.