Al Qaeda's Body Bombs: Al-Asiri's Next Threat After the explosion, as the air cleared in a Saudi villa, the grotesque remains of the suicide bomber littered the room. His mission on that night in August 2009 had been to murder Prince Mohammed bin Nayef, the head of the country's counter-terror operations. The would-be assassin had claimed he was giving himself up. He had said he would try to persuade others to surrender as well - but only if he could meet the prince in person. The Saudis flew the "repentant" terrorist from near the border with Yemen to Riyadh. They searched him. He carried no weapon that anyone could see. And then, as he met with the prince, suddenly, like something out of a horror movie, the man exploded. Saudi television showed the bomber's arm blown through the tiles of the suspended ceiling. A bare foot stood alone on the floor. The torso was sheered away below the waist. Bits of flesh stained the white furniture. Bin Nayef survived with only minor injuries. But a new age of terror - or attempted terror - had begun: that bomb was the first known prototype of a weapon all but undetectable by conventional security measures. Another version of it, a so-called underpants bomb, came close to exploding four months later on an American airliner bound for Detroit. And last week word leaked that a double agent - one run by bin Nayef - had successfully penetrated the same group of terrorists in Yemen, claiming that he, too, wanted to be a suicide bomber. The double agent had obtained the most recent, most sophisticated version of the device, turning it over to his Saudi handlers and their American friends from the Central Intelligence Agency. Are we safe yet? Not hardly, says Don Borelli, who was until recently one of the FBI's top agents in counterterrorism and now works with the Soufan Group in New York City. We got one of these things, but who knows how many more of them are out there? The man thought to have been the bomb maker is Ibrahim al-Asiri, who sent his own brother to die in the attempt to kill bin Nayef. "How many underlings does he have?" asks Borelli. How many apprentices are there to whom he's spread this knowledge so they can take up the work if he meets the business end of a drone strike? Worse still, intelligence is mounting that new terrorist bombs are under development that are meant to be implanted surgically inside a man or a woman (conjuring fears, not least, that someone who looks great with child could in fact be heavy with explosives). Last spring, U.S. intelligence officials began to pick up worrying information that al-Asiri was working with doctors on just such a project. Some dismissed the plan as far-fetched. But by last June, the CIA concluded that al-Asiri was close to being able to pull it off. Al-Asiri aims to devise a human bomb to evade airport body scanners. (From left: Phil Nobl; Saudi Interior Ministry / Reuters-Landov (2)) Newsweek has learned that U.S. intelligence officials circulated a secret report that laid out in vivid detail how doctors working for al-Asiri had developed the surgical technique. An American government source familiar with the report described it as 15 to 20 pages, single spaced, and replete with schematics and pictures. "It was almost like something you'd see in Scientific American," the source said. In military parlance, the bomb is called a "surgically implanted improvised explosive device," or SIIED. A diagram with arrows and blocks of text explained the surgical process. "The idea was to insert the device in the terrorist's love handle," says the U.S. government source, who declined to be named discussing sensitive intelligence. While it was not clear whether the terror doctors had ever succeeded in implanting explosives in a human being, they had experimented with dogs and other animals. Fortunately these devices are easier to describe than to detonate. "You would have to have a very unique firing system," says Borelli. "If it's a "body bomb" you are going to have to have a way to initiate it from the outside - almost a stent, or something like a pacemaker." And it's not least because of the technical challenges that, in fact, both of al-Asiri's suicide-bomb devices known to have been used were failures. In the attack on bin Nayef, the body of the bomber himself absorbed most of the explosive force. The pyrotechnic underwear of Umar Farouk Abdulmutallab, who tried to blow up the Northwestern jet to Detroit on Christmas Day 2009, fizzled instead of exploding. But as Borelli points out, "Even the threat of these devices causes a reaction by the security apparatus where we wind up spending millions of dollars." The body scanners now in many U.S. airports were installed to prevent a more deadly repeat of the Abdulmutallab incident. If SIIEDs could be perfected, however, even full-body scanners would not detect them. "We're certainly concerned," says a senior administration official, adding that al Qaeda terrorists in Yemen are always working on "newer and more innovative ways to conceal bombs, whether it be in cargo planes or surgically implanted IEDS." If scanners couldn't recognize such a device, security would depend on airport screeners spotting an "anomaly," the official said - such as an unusual bulge in a traveler's body - or detection by other means, including bomb-sniffing dogs and swabbing for explosive residues. It's precisely because of these uncertainties that the Obama administration has worked so hard to take the war to the enemy. Airport security is only the last line of defense. It takes the relentless disruption of al Qaeda operations in the field to prevent the old core group and its various spinoffs from spreading their terror far and wide. That's the purpose of drone attacks in Afghanistan, Pakistan, and Yemen. But when it comes to the fight on the ground in the Arabian Peninsula, bin Nayef is the pivotal player. His father, Prince Nayef bin Abdulaziz al-Saud, is, not insignificantly, the minister of interior and the heir apparent to the throne of Saudi Arabia. Behind Prince Mohammed's wire-rimmed glasses, the 52-year-old security chief is said to be scholarly, controlled, methodical, and relentless in pursuing the Kingdom's enemies. He has survived not only the bombing in Riyadh in 2009 but two other plots as well. The fight against al Qaeda in the Arabian Peninsula (AQAP) is for bin Nayef quite literally a duel to the death. The key is to get inside the enemy's camp. No one is better than the Americans at electronic surveillance, but human intelligence is vital, and for that, the Saudis are far better placed, as last week's double-agent saga shows. When bin Nayef and his agents learned that AQAP was actively seeking a volunteer bomber of a particular pedigree, they sensed an opportunity. "The Saudis are very strong in intelligence in Yemen, and they understand that the [AQAP] organization was looking for someone with a Western passport," says Mustafa Alani, director of the security and defense research program at the Gulf Research Center in Riyadh. So the Saudis, apparently with British assistance, found a spy who had lived in Britain, had an EU passport, and would be seen as a prize recruit by al-Asiri's minions. "He is someone recruited by the Saudis and sent to Yemen in the hopes that al Qaeda was going to pick him up and that is what happened," says Alani. The Americans were informed, but it was a Saudi operation. In addition to the bomb, the double agent may also have provided intelligence that was used to direct a later American drone strike against a top al Qaeda leader in Yemen, Fahd al-Quso, who played a major role in the bombing of the USS Cole in 2000. Other spies have also provided vital leads. One concerned Ahmed Said Saad, a Syrian medical doctor who appeared to be working with al-Asiri on his diabolical experiments. Around the time the document about body bombs was being circulated within the Obama administration, officials were debating whether Saad could be placed on the military's kill or capture list. Questions remained about the strength of the intelligence and the extent to which Saad could be tied to bomb development. Some officials questioned the propriety of targeting doctors who potentially saved lives. About two months ago, the questions became moot when Saad was killed in a CIA drone attack while traveling with another AQAP operative. Unfortunately, however, the battlefields in this twilight war are expanding, not narrowing. "At the one-year anniversary of bin Laden's demise, the tone is that it is all over, and that's all bullshit," says a veteran American intelligence official concerned with the ongoing threats. Sanctuary for al Qaeda-minded elements is probably greater than it has ever been. AQAP in Yemen controls more territory than ever, and al Qaeda spinoffs have emerged elsewhere - Somalia, Mali, the north of Nigeria, bits of Algeria, and parts of Libya. The bomb maker al-Asiri is still out there, training others. "I don't want to be the skunk at the picnic," says the intel official, "but if you are paid to worry about this you are going to focus on it, and when I focus on it, I worry a lot." With Aram Roston in Washington, D.C.