Other theories allege that government employees and officials, including US President Bill Clinton, knew of the impending bombing and intentionally failed to act on that knowledge.
Further theories allege that the bombing was perpetrated by government forces to frame and stigmatize the militia movement, which had grown following the controversial federal handlings of the Ruby Ridge and Waco incidents, and regain public support.
At 9:02 a.m. CST April 19, 1995, a Ryder rental truck containing more than 6,200 pounds (2,800 kg)[1] of ammonium nitrate fertilizer, nitromethane, and diesel fuel mixture was detonated in front of the north side of the nine-story Alfred P. Murrah Federal Building.
[3] Shortly after the explosion, Oklahoma State Trooper Charlie Hanger stopped 26-year-old Timothy McVeigh for driving a 1977 Mercury sedan without a license plate and arrested him for that offense and for unlawfully carrying a weapon.
After assembly, McVeigh allegedly drove the truck alone to Oklahoma City, lit the fuse, and fled in a getaway car he had parked in the area days prior.
[5] In 1997, the FBI arrested Michael Brescia, a member of Aryan Republican Army, who resembled an artist's rendering of John Doe 2 based on the eyewitness accounts.
"[6] Carol Howe, an informant for the Department of Alcohol, Tobacco and Firearms who had infiltrated the white supremacist enclave Elohim City, Oklahoma, filed a report in January 1995 stating that Andreas Strassmeir, Elohim City's security chief, had spoken about destroying a Federal building and had visited the Murrah building with another man.
[7] Two days after the bombing, Howe reminded the ATF of the earlier report and urged investigation into a possible connection to Elohim City.
[11][12] This was because Terry Nichols traveled through the Philippines while Ramzi Yousef, who committed the 1993 World Trade Center bombing, was planning his Bojinka plot in Manila.
[19] It was claimed that this bomber was either in the building when the bombing occurred, or had previously been murdered, and McVeigh had left his body in the back of the Ryder truck to hide it in the explosion.
[28] Similarly, Air Force Brigadier General Benton K. Partin expressed an opinion that there must have been additional explosive charges inside the Murrah building.
"[38] Among other unresolved questions, Rohrabacher also criticized the FBI for not explaining how Nichols, who did not work steadily, paid for his several trips to the Philippines and had $20,000 cash; for not finding explosives concealed in Nichols's house until a decade after the bombing; for not explaining the "rush to rule out the existence of John Doe Number 2"; and for not thoroughly investigating possible connections between McVeigh and the Aryan Republican Army and Andreas Strassmeir.
[39] In March 2007, Danny Coulson, who served as deputy assistant director of FBI at the time of attacks, voiced his concerns and called for reopening of investigation.
[44] In November 2014, John R. Schindler, a former professor at the Naval War College and National Security Agency intelligence officer, wrote "It would be good if a serious re-look at OKBOMB’s many unanswered questions were established for the event", because of "the existence of important evidence indicating there’s something we should be talking about".