A bomber from the al Qaeda affiliate in Yemen sent to blow up a U.S.-bound airliner last month was actually a double agent who infiltrated the group and volunteered for the suicide mission, U.S. media reported on Tuesday. Working closely with the CIA, Saudi Arabia's intelligence agency placed the operative inside al Qaeda in the Arabian Peninsula, or AQAP, with the goal of convincing his handlers to give him a new type of non-metallic bomb for the mission, the Los Angeles Times reported. Western intelligence agencies have identified AQAP as among the most dangerous and determined al Qaeda affiliates in the world, dedicated in part to attacks on the West. The explosive device was intended to be smuggled aboard an aircraft undetected and then detonated. The double agent arranged instead to deliver the device to U.S. and other intelligence authorities waiting outside Yemen, the LA Times reported. The agent arrived safely in an unidentified country and is being debriefed. Experts at the FBI's bomb laboratory in Quantico, Virginia, are now analyzing the device to determine if it really could have evaded airport security, the newspaper said. If such a device could be brought on board an aircraft, it could in theory be detonated without the knowledge of aircraft passengers and crew. The main charge was a high-grade military explosive that "undoubtedly would have brought down an aircraft," the New York Times reported, citing a senior American official. It appeared to be an upgraded version of the so-called "underwear bomb" that failed to down a passenger jet over Detroit on Christmas Day 2009, the LA Times said. "Like that bomb, this device bears the forensic signature of feared al Qaeda bomb maker Ibrahim Hassan Asiri," who is believed to be hiding in Yemen, the LA Times Web site reported. The operation relied not on the high-tech and satellite surveillance for which the CIA has been known in recent years, but old-fashioned human intelligence work. It did, however, produce intelligence that helped the CIA locate top al Qaeda operative Fahd al-Qasaa, who was killed on Sunday when a CIA drone targeted him with a missile as he stepped out of his car in Yemen, the newspapers reported. Qasaa was thought by intelligence analysts to have played a role in the bombing of guided missile destroyer USS Cole in a Yemeni port in 2000.