A CIA informant posed as a suicide bomber in order to persuade the al-Qaeda branch in Yemen to hand over a new, more sophisticated underwear bomb. 

The operation was a joint effort between the CIA and Saudi Arabia intelligence. 

The bomber, who we now know was a double agent, had been instructed by al-Qaeda to choose a U.S.-bound flight to target, but that the bomber had not yet bought his tickets.  

The informant arranged to deliver the explosive devices to U.S. and other intelligence authorities waiting in another country when he recieved the bomb, officials said.

(h/t WFLD-CHI (FOX) )