Revealed: How Christmas Day bomber's exploding underwear failed to detonate... because he had worn them for THREE WEEKS



Agents who investigated Umar Farouk Abdulmutallab said he was forthcoming about his plans

Abdulmutallab sentenced to three life terms after pleading guilty earlier this year

Infamous al-Qaeda bombmaker Ibrahim Hassan al-Asiri is believed to have made the device

The notorious underwear bomber who tried to bring down a jumbo jet on Christmas Day had a dirty little secret - he'd been wearing the explosive skivvies for weeks.

Umar Farouk Abdulmutallab wore them for three weeks to be exact, and it may have been the reason why he was unsuccessful in his 2009 terrorist plans aboard a Detroit-bound airliner.

The new details were revealed by two FBI agents who played a role in securing a confession from Abdulmutallab, shortly after the bungled plot.

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Bomber shorts: Umar Farouk Abdulmutallab wore this underwear outfitted with explosives for three weeks before the failed bomb attempt on Christmas Day 2009

Notorious: Abdulmutallab was focused on his mission to crash the plane over Detroit, because it was 'God's call'

Agent Ted Peissig told WXYZ-TV : 'So basically for three weeks he wore this garment, these underwear with this device in it.

‘We think ultimately that is probably what caused the disruption in the sequence of events in the explosion.'

Terror strike: Abdulmutallab, pictured in his 2009 mugshot, was sentenced to three life terms after pleading guilty

Peissig, along with fellow agent Mike Connelly, told the network that Abdulmutallab wore the explosives-rigged underwear for three weeks in an effort to get accustomed to it, only taking it off when he showered.

Connelly added that Abdulmutallab was focused on his mission to crash the plane, because it was 'God's call.'

The agents admitted that Abdulmutallab did not look like a terrorist, but he spoke freely about how he was working for al-Qaeda and that had acted alone.

The explosives failed to fully detonate aboard the flight, which was carrying nearly 300 people, but caused a brief fire that badly burned his groin.

Passengers pounced on Abdulmutallab and forced him to the front of Northwest Airlines Flight 253 where he was held until the plane landed minutes later.

Abdulmutallab talked freely to the FBI about his desire to commit martyrdom for his Islamic faith.

In 2009, months before the attack, he said he travelled to Yemen to see Anwar al-Awlaki, an American-born cleric and one of the best-known al-Qaeda figures.

He told investigators that his mission was approved after a three-day visit with his mentor.

Al-Awlaki and the bomb maker were killed in a U.S. drone strike in Yemen last year, just days before Abdulmutallab's trial.



Agents: Ted Peissig, left, and Mike Connelly are the two FBI agents who were able to secure a confession from Abdulmutallab after the failed bomb plot



At the time, President Obama publicly blamed al-Awlaki for the terrorism plot.

For their role in the Abdulmutallab investigation, Peissig and Connelly were recently given the Attorney General's award, the highest honour an FBI agent can get, according to WXYZ-TV.