National security sources tell ABC News that the al Qaeda terrorist who tried to kill Saudi prince and counterintelligence chief Prince Mohammed bin Nayef in August used the same technique -- an underwear bomb -- and the same PETN explosive that Umar Farouq Abdulmutallab tried to use in his attempted Christmas Day attack.
Within a week of that failed August attack on Prince Mohammed, President Obama dispatched his top counterterrorism and homeland security adviser John Brennan to Saudi Arabia to meet with Prince Mohammed to discuss the attempt, a senior administration official told ABC News.
That September visit "started the process by which we worked with Saudis on the forensics of the attack and the technique, which we did over the next several weeks," the official said. "That information was shared widely within the government."
White House press secretary Robert Gibbs said on Sept. 1 that the "attempt on the life of Prince Muhammad underscores the continued threat posed by al Qaeda and the importance of strong counterterrorism cooperation between the United States and our regional partners. The president has discussed security cooperation in all of his interactions with King Abdullah of Saudi Arabia, as they both share a firm commitment to dismantle the al Qaeda organization and to prevent it from carrying out its murderous agenda."
In October, Prince Mohammed visited to U.S. as part of the "continued efforts to coordinate with the Saudis," the official said, with Prince Mohammed sharing more information on al Qaeda in the Arabian Peninsula and also the new techniques.
Al Qaeda operative Abdullah Hasan Tali al-Asiri -- on Saudi Arabia's February 2009 list of its 85 most wanted terrorists -- had fled to Yemen. But in August he contacted Prince Mohammed's office to purportedly participate in Saudi Arabia's amnesty program.
"I need to meet you to tell you the whole story," Asiri told the prince, according to a recording broadcast by Saudi-owned Al Arabiya .
"If you come, I will sit with you," the prince said.
Meeting with Prince Mohammed, Asiri detonated the explosive but killed only himself .
Originally, the bomb was thought to have been hidden inside Asiri's rectum, but further forensics revealed it had been part of an underwear bomb.
UPDATE: ABC News' astute Kim Randolph adds that Brennan this morning told NBC that "right after that (August) attack, I went out, I met with Prince Mohammed Bin Naif. I, in fact, saw the room where the attempted assassination took place. That information was provided to us by the Saudi government. We disseminated information broadly. There was no indication, though, that al Qaeda was trying to use that type of attack and that modus operandi against aircraft. We were very concerned about it from an assassination standpoint, and we continue to look at all the evidence that is out there so we can take the steps necessary to prevent any types of attack from taking place."
And on CNN he said, "within a week of that attack, I was out in Saudi Arabia. I met with Prince Mohammed bin Nayef. I went to the room where the attack took place. We worked very closely with the Saudis to get that information. We shared it completely throughout the government. PETN was the substance that was used in that attack. We were looking very carefully at that. There was no indication at the time that there was going to be an attempt against an aircraft. What we need to do is to try to stay ahead of it."
Asked if the FAA was put on alert, Brennan said, "there was nothing in that assassination attempt against Prince Mohammed bin Nayef that indicated aviation was a target...The suicide bomber came in next to him. We were very concerned about the possible assassination attempts."