The more I watch this episode, the more I like it. The beauty of this episode is that it feels real. You think that maybe Harold does have SOME feelings for Elizabeth and that his lavish spending on gadgets is, in his mind, necessary. His brother in law defends the company's performance by agreeing that its mainly due the recession, so you think maybe be is an egomaniac running the company into the ground, but he isn't totally incompetent. So like all family problems, it's not a black and white situation. Fe house and the actors are all beautiful, making it fun to watch. (Gena Rowland's looks like a movie star!)
A few things...
1) The cameras were motion/light/heat activated only. They did not record all day and would therefore stop recording after the murderer left the room.
2) Harold's explanation that the cameras were installed in the house to prevent a robbery of the safe, and not a murder, is ingenious and makes the whole plot plausible.
3) Martha Scott's threat to put her silly son in charge of the company shows that she was also fallible, and gives us reason to be more understanding of Harold's motives (although we certainly can't condone the murder).
4) the most interesting part of movie not explored was Elizabeth saying that she should become temporary chairwoman. Obviously, she knew there were troubles but why would she step over her brother when her brother was already a company executive?
5) worst part of movie is columbo's statement that his wife does "painting by the numbers". This is cringe-worthy and does not fit into the character of the clever Mrs. Columbo that's been hinted at previously.