Some deductions

As you gaze out the window your mind mulls over the lists you've found and what meaning they might have. Obviously they were meant to be hidden, and the most likely candidate for doing so was the teacher who used this classroom last year. Assuming that all the names belong to students there seems no reason to hide the list, but nonetheless it was hidden, and in your experience people don't conceal things for no reason.

Confirming that all the names are students seems the logical first step. You open the folder you were given at the faculty meeting last night and pull out the student list. It takes you a few minutes to determine that exactly half of the names on the first list are current students, as are all of the names on the second. You look over the names that aren't current students, and one of them suddenly jumps off the page at you.

Veronica Samuels. The student who was killed by a train last spring. The 'Ronnie' that Chanel screamed about.