Murder, a Self Portrait - S9-E1
Character mistake: When Columbo is asking Barsini about one particular artist paintbrush, Barsini says it is a fluffy sable brush. It's actually one made from pig bristle. Natural sable brushes are soft red fur, while pig bristles are stiffer and a light beige color. There's no mistaking the two, and any experienced artist knows the difference.
Character mistake: Columbo took the Beretta off the gun display by inserting a pencil into the barrel of the gun. In a previous episode, he said to NEVER insert a pencil there because it will ruin the groove of the barrel, making it impossible for ballistics to get a match on the bulletin. When using a pencil, Columbo picks up a gun up near the trigger.
Continuity mistake: Columbo stops Mr. Finch on the road after following him from Biltmore hotel; as Columbo is speaking with him, the cigar in Columbo's hand is always in Finch's shot, even after we see Columbo place his hand on the roof. Plus after we see him put his hand down, the cigar ash keeps going from 1" to nothing. (01:44:20)
Other mistake: In the home of a murder victim, Columbo presses the telephone's "redial" button to see who was called most recently. A seven-digit number is displayed but only six beeps are heard as the number is redialed. Later, attorney Oscar Finch places a call by dialing only five numbers.
Continuity mistake: At the end, when Columbo is demonstrating on the mannequin, his cigar changes position between shots.
Answer: Columbo deduces that the first blow must have been to the front of the head, the force causing the victim to fall backwards and hit the back of his head hard on the ground.
raywest ★