One thing has always bothered me about Margaret's big next-to-last scene with Leslie. Since she and Columbo are working together by then, how much of what she does in the scene does he actually know about beforehand? It bothers me that he would approve of her getting a gun and firing blanks at Leslie, especially since something obvious could somehow go wrong. So it bothers me that anyone in the police would approve of it, and blanks or no blanks, that's especially true of gun-hating Columbo!

So did he know about that part ahead of time?

Good question. I'd never really thought of that before, but it makes sense. Margaret sat in the same seat that Leslie did, a piece of evidence Columbo could have deduced from the angle of the bullet entry (assuming the remains allowed that kind of deduction).

Did he give her the plane transponder, too?

i am also wondering who confronted her with the plane trasponder/beacon and how it was found.
i guess it's obvious columbo gave it to margret for shock value.

this scene would work great as a nightware sequence, if the killer had any remorse.