I think the tarot card was left by a seventh grader or two who goes to the school and was left perhaps days before when they held some kind of 'fun' afterschool readings in the nearby woods experimenting with the occult. The policemen note was written after a they were harrased for skateboarding in the giant parkinglot. In the hope of occult type revenge, I doubt it's related and is why the cops didn't want it to get out.