The water sprayed on the pool side by Paul Hanlon would evaporate in the Californian heat in minutes. Yet when Columbo arrives the water is still there for him to taste.
As Columbo sits in his car listening to the Rockets game on the car radio, his cigar ash falls on his raincoat, and the size of his stubby stogie is barely a butt. Seconds later, the cigar is back to almost full size.
As Hanlon's secretary greets lawyer Cunnell, she holds a telephone receiver in her left hand. In the following scene Columbo enters the room and suddenly the receiver is on-hook again, while the phone starts ringing.
Columbo is listening to the recording of the last phone call while he's sitting in the Ocean Side East Cafe, when Dobbs comes in. Columbo gets out of the booth and walks outside with Dobbs. A cafe worker wipes down the table, but the tape recorder is not on the table and neither the Lieutenant nor Doobs has it in their hands.
CORRECTION: Columbo has the recorder in his left hand when he stands up. He switches it to his right hand for the rest of the scene.
When Hanlon calls Wagner the second time, Wagner is reposing at the bottom of the slide and he answers a telephone sitting on the ledge to the right of the slide. When Columbo inspects the pool area the slide is seen in the background, but the telephone is no longer visible.
Since the phones in both Wagner's house and Hanlon's office are bugged, then there ought to have been two recordings of Hanlon's call to the house: one from the bug in the office, and another from the bug in the house. But as Hanlon made the call from an outside phone and not from the phone in his office, Columbo all along had proof of Hanlon's guilt, had he checked the phone recordings from the office and not found one for the call to the Wagner house.
When Shirley Wagner lands at the airport, the wheels of her plane are shown touching down. The wheels are of a B-52 bomber and not a commercial airliner.
When Hanlon whacks Eric with the chunk of ice, such an injury would have left a bloody gash. But no blood is seen in the water.
At the start of the game after the kickoff, it is 1st and 10 at the 38 yard line. The quarterback is sacked for a 5 yard loss and the radio announcer states that it is now 2nd and 15 but the ball is on the 30 yard line. That should make it 2nd and 18. The problem here is that there was no attempt to be sure the script matched the archived footage used in the broadcast.
The footage of the airliner's landing gear uses obvious stock footage of a B-52 jet bomber.
The radio in Columbo's Peugeot appears to be a European model with a frequency band not compatible with American AM radio. Therefore, he would not be able to tune in to an American station to listen to the football game on his car radio.
When Hanlon is leaving the stadium during the national anthem, only a few of the extras are holding their right hands over their hearts, which is the custom in the United States. The U.S. Flag Code says, "During a rendition of the national anthem when the flag is displayed all present except those in uniform should stand at attention facing the flag with the right hand over the heart."
By the time the police are notified about the death, it is already half time of the football game. A half of a football game usually takes an hour and a half. Yet the police show up at the house, wait for lieutenant Columbo who arrives and looks over the crime scene and then has time to get back to the stadium while the game is still going on. Highly unlikely.
When Shirley Wagner arrives at the airport, a person with a TWA Airline Captain uniform is carrying her luggage. It is highly unusual for the Captain to carry passenger's luggage after the flight.
As the little girl comes up to the ice cream truck, she yells for it to stop, but it isn't even moving. Then she stands at the back of the truck instead of trying to make sure that the driver can see her.
Hanlon hits Wagner while he is facing him; as a result, he falls backwards into the water. He then is shown floating in the water face down with no explanation for how he rolled over.
The coroner thinks that Wagner hit his head on diving board - but there is no reason for him to think this, as there would have been no blood on the diving board to show that.