Six months after 9/11, a man with a menacing moniker brought Chicago's transit system to a standstill when he was arrested with a vial of cyanide. Dr. Chaos told police he was keeping more than a pound of the dangerous chemical in an underground CTA storage closet. So... who is Dr. Chaos? And what was he planning? Find out, in this WGN-TV original podcast... Chasing Chaos.