https://thepostmillennial.com/fbi-thwarts-teens-plans-for-mass-shooting-and-bomb-attack-at-wa-mall
"Authorities say the plot included detailed blueprints of the mall, a designated attack route, and a plan to use a chlorine-based improvised explosive device to spark panic. The suspect allegedly intended to open fire on moviegoers as they fled the theater, then take own life at a predetermined location inside the mall. "