Three tells for predicting the 'who' in a movie whodunit

Kenneth Branagh's "Murder on the Orient Express," based on Agatha Christie's classic 1934 mystery novel, opens Nov. 10. If the killer isn't the same as the 1974 Oscar-winning movie of the same title, this presents an ideal opportunity to test my three tells for predicting the "who" in a whodunit.

Tell No. 1, the easiest, states that when a famous star plays a seemingly insignificant or small supporting part, he/she will summarily be unmasked as the killer.

The current thriller "Geostorm" uses that rule. So did "Angels & Demons," "Kiss the Girls," "Sea of Love" and many more.

But it doesn't apply to "Murder on the Orient Express" because, like the 1974 feature, the entire cast consists of name stars.

So on to Tell No. 2: The killer will be the main character's trusted confidant, a best friend ("Strange Days"), mentor ("Minority Report"), business partner ("Ghost") and/or close family member.

This tell may not apply to "Murder on the Orient Express" if Branagh's main character, Hercule Poirot, has no trusted ally in this screenplay. (Chicago critics will see the movie Nov. 7.)

Finally, Tell 3 states that the mystery villain will be fingered by conspicuous goodness. Most of the characters will possess motives for the murder, appear shifty or suspect. Look for the kind heart, overt empathy or gushing appreciation and you've nailed the killer. (Check out "The Snowman.")