An improvised explosive device (IED) used by perpetrator Anthony Warner to carry the Nashville bombing on Christmas Day was likely a thermobaric bomb, Federal Bureau of Investigation (FBI) expert Dave Williams told the website SpyTalk.
A thermobaric weapon, also known as a vacuum bomb, is a type of explosive that uses oxygen from the surrounding air to generate a high-temperature explosion.
Williams insisted that FBI investigators have “never seen an improvised thermobaric device before” in the US “or any country”, among the bombing attacks launched by IED-makers throughout the world.
“The reason is, it’s very difficult to get the timing down to get an optimum mixture of air and a liquefied carbonaceous fuel such as propane, methane, acetylene or natural gas. He [Warner] couldn’t have done it the first time and made it work. There had to be a test area,” Williams argued.
His theory is partly based on the pattern of destruction as well as the videos of the Nashville blast which show a yellow-orange fireball and very little smoke from the bomb itself, which suggests that the explosion was rather efficient.
Williams was echoed by an unnamed retired senior FBI agent and bomb expert, who claimed that a version about an unprecedented fuel-air IED used by Warner was “very plausible”.
“We know he ‘tinkered’ on his RV for a long time so he would be able to easily seal it tight to allow any gas to accumulate. He had more than enough electrical expertise to construct a timer and initiator that would function when he passed out,” the ex-FBI agent was cited by SpyTalk as saying.
They added that the only way to prove the theory “for sure will be through chemical analysis of any charred remains in the pieces of the RV they recover”.
According to the expert, “the visual of the [Nashville] explosion sounds like a fuel-air device, but to confirm it, they will have to do a frame-by-frame examination of all video and a gas chromatography—mass spectrometry analysis of any of the residues”.
The remarks come a few days after media reports that in August 2019, Warner’s former girlfriend told Nashville police that he was “building bombs in the RV trailer” on his property and “frequently talks about the military and bomb-making”.
The police reportedly referred the incident to the FBI, but neither agency obtained a search warrant to finally investigate Warner’s premises in the wake of his ex-girlfriend’s information.
Eight days after the incident, the FBI is still trying to find a motive behind the 63-year-old freelance IT consultant blowing an RV in downtown Nashville, an explosion that injured at least eight people and seriously damaged about 40 buildings in the area.