Poor Lois Duncan. She's written many good-to-excellent thrillers aimed at the teen set, but their video adaptations almost never do them justice. "I Know What You Did Last Summer" was turned into a teen slasher flick; "Gallows Hill" was butchered into "I've Been Waiting for You", and "Don't Look Behind You" (one of Duncan's best, about a girl whose family enters Witness Relocation) was turned into a vehicle for "Dallas" has-been Patrick Duffy! Only "Summer of Fear", aka "Stranger in Our House", managed to survive intact (though you still have to put up with the dog/horse plot switch, as well as Linda Blair's scary perm).
The "Killing Mr. Griffin" movie, sad to say, is a middling effort, not at all worthy of the excellent source material. Most of the characters survive the transition to the screen, but are watered down and robbed of their distinctive traits. Mr. Griffin himself, a well-meaning guy who has trouble relating to kids in the book, is simply a jerk here. But worse is what happens to Mark Kinney. In the book, it is slowly and frighteningly revealed that Mark is actually a sociopath, whose history of violence and ability bend the group to his will is even more troubling than what happens to Mr. Griffin. But in the movie, Mark is just another troubled kid who is reacting to the pressure his parents have put on him to succeed. Too bad, because his original incarnation is much, much scarier.
If you haven't read the book, I highly recommend it, as well as the other books I've mentioned above. It would be a much better use of your time.
