Transportation Security Administration chief John Pistole offered specific details Friday about a new "underwear bomb" designed by an al-Qaeda mastermind and meant to be exploded in an airliner over the United States last year, Time reports.
The plot was stopped thanks to work by a double-agent inside al-Qaeda’s Yemen branch, in a case that's also been the subject of a Justice Department leak investigation:
In an exchange with ABC News reporter Brian Ross at the 2013 Aspen Security Forum, Pistole described the bomb as "Underwear 2," a successor to the underwear bomb worn Umar Farouk Abdulmutallab tried to detonate on Northwest Flight 253 near Detroit on Christmas Day 2009. Abdulmutallab’s bomb fizzled, severely injuring his groin but no one else.
Pistole described the May 2012 bomb as "a next generation device" that was "new and improved in many respects" from the Christmas 2009 bomb. Designed by one of the most wanted terrorists in the world, Ibrahim al-Asiri, the device featured "a new type of explosive that we had never seen," Pistole said. "All of our explosive detection equipment… wasn’t calibrated to detect that. And all of our 800 bomb-sniffing dogs had not been trained for that specific type."
The use of a new explosive has been previously reported, but Pistole continued with less familiar details about Underwear 2 that reflect the growing sophistication of Asiri’s sinister craftsmanship. He said the device included redundancy, by mean of two different syringes to mix liquid explosive compounds–"a double initiation system," apparently a response to a failure of Abdulmutallab’s initiation process. In essence, Pistole said, "they made two devices."
Pistole added the bomb was encased in caulk, trapping vapors that would otherwise attract the attention of bomb-sniffing machines or dogs:
"So you really have a twisted genius in Yemen," Ross observed. "That is our greatest threat," Pistole replied. "All the intel folks here [at the forum] know that is a clear and present danger."