One checked in at Birmingham to connect through ORD to AMS. He was flagged as suspicious in BHM, but as they couldn't find explosives they allowed him to continue to travel. The guy who boarded in BHM apparently collected his bags in ORD and rechecked them on a flight connecting in IAD to DXB, but actually boarded the ORD-AMS flight. The flight to IAD departed, but the bag was confiscated once it was realized he wasn't on that flight. The suspect that boarded in BHM lived in Detroit but was originally from Yemen. Not sure where the second guy who "joined" him was from.

There looks to be a couple of "opportunities" for TSA in this incident that I am sure will come to light in the subsequent investigation.