Series producer Robert Sherman directed and wrote this episode (perhaps a cost cutting move), which reminded me, to a degree, of stories from the first two seasons. At that time of the series, Barnaby dealt with some exceptionally strange individuals, but who were extremely crafty.
Such is the case here; Jacqueline Scott and Michael Strong play the parents of a young man who is a deranged killer. The catch is both Scott (as Verna) and Strong (as Stuart) are as desperate as their son, and will go to extremes to protect him. Enter Betty who assists them in finding their son, winding up in a tight spot. Wait and see.
This is a wild episode, and exceptionally acted, particularly on the part of Jacqueline Scott, who was in many Quinn Martin productions. Likewise Michael Strong, though his part is smaller. I agree with the last reviewer, there's an interesting scene where Betty wakes up one morning to find Verna and Stuart very much at home in her kitchen cooking breakfast, playing it all cool. Clearly Verna is the brains of the outfit.
This also brings to mind an earlier and similar episode (a few seasons back) co-starring David Wayne and Eileen Heckert as a bizarre couple, Heckert the leader of the pack, only they murdered members of their own family to gain an inheritence. Director and writer Robert Sherman keeps up the suspense, and Scott should have earned an Emmy, at least for her decades of fine work.
From SEASON 6 EPISODE 20 remastered color/CBS.