If a suicide bomber struck outside a stadium packed with 84,000 people smack dab in the middle of America’s heartland, you’d think you might hear about it. That’s exactly what happened outside a University of Oklahoma football game last Saturday.

Just days before he blew himself up, Joel Henry Hinrichs III tried unsuccessfully to buy large quantities of ammonium nitrate, the main ingredient used in the 1995 Oklahoma City bombing that killed 168 people. Instead, Hinrichs used TATP, the same explosive used by the recent London bombers and failed “shoe bomber” Richard Reid. TATP is highly unstable and can explode spontaneously, raising the possibility that Hinrichs’s bomb detonated before he had intended. Other evidence also suggests that Hinrichs had more ambitious plans:

Officials confirmed Sunday a cache of explosive material later was found inside Hinrichs’ residence at the university-owned Parkview Apartments [...]

Meanwhile, an Oklahoma television station is reporting that Hinrichs attended the same mosque in Norman, Oklahoma as Zacarias Moussaoui, who was convicted of conspiracy in connection with the September 11th, 2001 attacks on New York and Washington.

The FBI and the Joint Terrorism Task Force are investigating [PDF file; 181KB].