Continuity mistake: At the very end Fleming sees the dead body of his girlfriend being hoisted onto a gurney - she is soaking wet, having been hauled out of the swimming pool. Later we see it is a policewoman acting as a stand-in in order to fool him into talking - and after a few minutes under a blanket on the gurney she, her bikini, and her hair are all bone dry. Not only that, her hair looks like it has just been styled and her makeup is perfect.
Audio problem: There is a scene where the mistress of the murderer enters his bureau. You see her push the door closed while hastening through. You can hear the door lock click - but a half second too early. Her push wasn't that strong. (00:47:05)
Revealing mistake: Just after the scene where the doctor asks Columbo to switch off the light before leaving, the detective does so, but it can be seen that both light switches are down before he does this, and that they are still both in the down position after he "switches off" the light.Dale Adams
Character mistake: After Fleming has murdered his wife, he warns his girlfriend not to touch anything in the apartment, but he hands her a drink which he already prepared for her. At his direction she also makes a telephone call, holding the receiver with a cloth he hands her, but dialling the number with her bare fingers. On top of that, he hands her a pair of gloves after she has made the call - she would have touched or handled all sorts of things in the room by then. Why didn't he hand her the gloves as soon as she stepped in the room?
Continuity mistake: When the girlfriend speaks to the cleaners the phone is on the bar, and then they leave for the airplane. When Mr. Fleming comes back the phone is on the table.