History

Oklahoma City Bombing: The 'Second Bomb' Theory

On 19 April 1995, a truck bomb destroyed much of the Alfred P. Murrah Federal Building in Oklahoma City and killed 168 people. Timothy McVeigh was convicted and executed. Some critics have argued that extra explosives inside the building were involved. U.S. Geological Survey scientists found that the seismic signals cited as proof of a second blast are consistent with a single explosion.

By The Tinfoil Tribune StaffEra: 1995–present · Verdict: Debunked
'Empty Chairs and Fog' at the Oklahoma City National Memorial. Each chair honors a person killed in the bombing.
'Empty Chairs and Fog' at the Oklahoma City National Memorial. Each chair honors a person killed in the bombing. Photo: G. Edward Johnson / CC BY 4.0, via Wikimedia Commons

Verdict: Debunked. The weight of the evidence cited below contradicts this claim. How we rate stories

The Story

At 9:02 a.m. on 19 April 1995, a bomb in a rented Ryder truck blew up outside the Alfred P. Murrah Federal Building in downtown Oklahoma City. According to the FBI, 168 people were killed, including 19 children. About 90 minutes after the blast, an Oklahoma state trooper stopped Timothy McVeigh, an ex-Army soldier, for a missing license plate. Evidence soon tied him to the attack. The FBI says his friend Terry Nichols helped build the bomb, and another man, Michael Fortier, was aware of the plot.

Doubts started soon after. A seismograph about 26 km from the city recorded two wave trains about 10 seconds apart, and the public release of that record prompted speculation that there had been two explosions. Some critics argued that the truck bomb could not have caused the damage alone and that charges must have been placed inside.

Geologists found the two seismic signals were consistent with a single blast.

Scientists looked closely at the recordings. A U.S. Geological Survey team concluded that the two wave trains were 'consistent with a single impulsive energy source,' representing seismic waves traveling at different velocities. When the ruined building was demolished on 23 May 1995, that single event also produced two wave trains.

McVeigh was found guilty and executed on 11 June 2001. Nichols was sentenced to life in prison with no parole, and Fortier to 12 years, according to the Oklahoma Historical Society. The FBI conducted more than 28,000 interviews in what it calls one of the most exhaustive investigations in its history. No second bomb has ever been found.

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Origins

According to the FBI, McVeigh parked a rented Ryder truck carrying a bomb in front of the Murrah building, and it exploded at 9:02 a.m. Speculation about a second explosion was prompted partly by the public release of a seismic recording that showed two signals, according to the U.S. Geological Survey.

The Claims

Key Evidence

Fact Check Debunked

The Evidence Against

  • The U.S. Geological Survey found that the two wave trains were 'consistent with a single impulsive energy source.' The recordings indicated seismic waves traveling at different velocities. The 23 May 1995 demolition of the building's remains also produced two wave trains.
  • According to the Oklahoma Historical Society, McVeigh was found guilty on all counts and executed on 11 June 2001. Terry Nichols was convicted of conspiracy and manslaughter and sentenced to life in prison with no parole. Michael Fortier, who the FBI says was aware of the plot, was sentenced to 12 years in prison.
  • The FBI describes the investigation as one of the most exhaustive in its history, with more than 28,000 interviews and more than 43,000 investigative leads.

Documents & Sources

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