After the incident , speculation began immediately about Hinrichs ' motivation and the number of accomplices , if any . An off-duty police officer noted a discussion Hinrichs had with a local feed store owner about ammonium nitrate and had begun an investigation , one heightened by innuendo regarding the Pakistani heritage of the bomber 's roommate . Terrorism-related speculation further erupted when the explosive agent was found to be TATP , an explosive of similar manufacture , though separate makeup , to the compound used in the July 2005 London bombings , as well as in an attempt to destroy a transatlantic flight by igniting a shoe and by Hamas in clandestine devices intended for detonation by suicide bombers . The Federal Bureau of Investigation ( FBI ) and local authorities concluded in 2006 that Hinrichs was alone and had no assistance from other groups , but could not prove or disprove allegations that Hinrichs intended to enter the packed stadium and kill football fans along with himself
July 2005 London bombings
7 July 2005 London bombings
2005 University of Oklahoma bombing