Mystery LAD

There are 350 people watching a film called "In the Mist", an action and romance movie. But instead, a killer says on the speakers that he wants you to figure out who the killer is in a short movie he made. He says that if you don't figure it out until forty minutes, the everyone in the theater will die. He says not to try to get help from anything but electronics, then says, "Oh, I also should say that you must not fully trust anyone. I-I'm in the same room as you as we speak. I'm not one to give up easily. Oh yes, the film is called "You'll Never See It Coming", goodbye". The screen then turns bright and shows the film. After the film, three high school students try to crack the case. Will they figure it out in time?