The odd thing is, this story isn't the only time Donald Pleasence is blackmailed into marriage (or almost blackmailed into it in the case of this story). There's a dark comedy I barely know called ARTHUR? ARTHUR! where it happens to him after a killing.
He was a very good actor, always seemed (the core personality behind his acting), claustrophobic type, a bit stiffly cautious and or guarded. But 2 ironically important areas in this particular episode, I felt or found related to this actor in it, was one, it presented Columbo to sincerely like him and find him a nice harmless uncomplicated man? Second, I found (I could be wrong), unlike some bad-guy characters in the series, played more than once, he played only in this? Anyway, just like most of the 70's episodes being well made with more developed stories, this one was well made.