Great points Cassa. Very interesting about the possibility of Dudek defecting. I hadn't thought of that before. And what is that about the 6 numbers instead of 7...I think I missed the point there.
Good stuff Cassa

And how did Clayton talk on the phone to a travel agent when he had already broken his hearing aid?

Joe

How about this one:

While sitting in the French restaurant with Emmett Clayton discussing the case, Columbo makes reference to an inconsistency about the supposed accident (I think it was about Dudek forgetting to pack his chess set) by saying that it kept him awake the previous evening. The conversation was supposed to take place on the same day as the attempted murder, meaning that it would not have yet happened when Columbo was trying to sleep on the previous evening.

Paul..the thing about the 6 numbers rather than 7 is just another goof in the episode. Here in the US telephone numbers are 7 digits long.......and then if you have to dial the area code, they are 9 digits long and then sometimes you have to dial a 1 before the area code...and.....ok I'll stop!!!!
Joe very good point...but could it be that the hearing aid was just starting to go on the fritz and then later it went out completely...and he is not wearing his hearing aid when he shoves Dudek into the trasher. But another moment that is a little vague is when that reporter calls him to ask for an interview and Clayton is holding the receiver to his mouth but the other end of the phone is not attached to his hearing aid...how does he hear him?
And David excellent point about the sleeping thing..it was all the same day.

The first time Clayton breaks into Dudek's room he puts tape over the lock, but the second time he just unlocks the door and luckily Dudek's doctor doesn't lock it on his way out. The door/lock also look different. I never understood why he didn't just tape it again.

I also wondered how Linda Robinson went from being Clayton's girlfriend to Dudek's sidekick. I could easily see her breaking up with Clayton, but did she move to the Soviet Union and start hanging out with Dudek? How could that have really happened? Maybe she wanted revenge for some reason, but that seems a little extreme!

That's right E...and if you remember when the guy is in the room packing up the stuff he leaves the door ajar...and Clayton can easily slip his hand in and undo the lock...why didn't the guy lock the door on his way out? And as you pointed out, why didn't Clayton use the tape again?
That was a great point you made about Linda Robinson. Clayton was an American so she would have been with him in the states. I think maybe your revenge idea was pretty good!

Oh Dear!!! The above post was from me...not cassavetes 34!!! Since we had a power outage about a week or so ago I have to type my name in every time I make a post....
So I wasn't trying to impersonate myself...I just mistyped!!!