My wife and I have been watching an array of television mysteries. As I have noted, one way to determine who the murderer is in any contemporary American television drama is to notice which character is the most religious. He or she will almost invariably be the killer.
Since religion is often not evident at all in the TV universe, this rule will not be applicable to every episode. But we have devised another rule: If a guest star from any of the old Star Trek series appears in the episode, he or she will be the killer.
Spoiler alert: In a recent Criminal Minds marathon that my wife and I indulged in last weekend (don’t ask why), three successive episodes featured the actors who played Wesley Crusher, Neelix, and Odo, all of whom provided evidence for our hypothesis.