aww...poor mrs. peck is being raked over the coals...
but i can understand, her character was a bit over-the-top. but darnit! i just found her so funny. and there were the tender moments between her and columbo when he was explaining how he has always been a bit messy and such, and then she offers him the health cookies and milk..that was a very touching scene. and in the last scene where she is so upset about finding out that the 'boys' were indeed the murderers, just look at columbo's face and hers as well..he hated to disappoint her so..
It isn't the phone conversations alone that prove the guilt of the twins, it is also Columbo's demonstration that the crime could not have been committed by one person alone. So if there were two people involved in the crime, the only "pair" of suspects that Columbo has are the twins. Still only circumstantial I suppose, but a bit more solid than some of the other circumstantial endings.