On April 19, 1995, the deadliest domestic terror attack on U.S. soil occurred at the Alfred P. Murrah Federal Building in Oklahoma City. The bombing, carried out by Timothy McVeigh and Terry Nichols, left 168 people dead and more than six hundred injured. McVeigh and Nichols parked a Ryder truck containing a 4,800-pound bomb near the freight entrance of the building and detonated the bomb. Damage from the explosion spread blocks away from the building, and could be heard from miles away. AS WE WATCHED uses archival footage from ABC News to detail how law enforcement and the FBI tried to piece together who could have carried such an attack. The special documents every moment of the FBI investigation, from the initial bombing to the eventual arrest and conviction of Timothy McVeigh and Terry Nichols.