Who killed the Prom Committee (revised)

"Someone help me!! My daughter is in one of the classrooms and she's not breathing" "Ma'am please calm down." "Hey there's a guy lying in his own blood in the men's room" "Lacey, Leah is in the lobby and she's been hung" "Mars is in the main office and there's blood everywhere" "Lacey come quick, Ian's in the teachers...