Stink Bomb: Underwear Bomber Wore Explosive Undies for Weeks, FBI Says

The notorious underwear bomber’s explosives failed to go off during the 2009 Christmas Day plot because he wore the potentially deadly undies for three weeks before trying to detonate them, FBI agents involved in the investigation said.

Two FBI agents told ABC News’ Detroit affiliate WXYZ in an exclusive interview that when the bomber, Umar Farouk Abdulmutallab, confessed to the plot, he went on to say that he had worn the explosive underwear for three weeks in order to get used to it and make sure he could get it through security.

“We think ultimately, that probably is what caused a little bit of separation in the sequence of events in the explosion,” said FBI agent Ted Peissig, who interrogated Abdulmutallab.

Abdulmutallab pleaded guilty last year to attempting to blow up Northwest Flight 253 over Detroit on Christmas Day in 2009. He  was able to get through security and onto the plane, but the underwear bomb he was wearing failed to detonate. Instead, it caught fire, severely burning Abdulmutallab.