Ibrahim Hassan al-Asiri, who runs a clandestine bomb factory in Yemen, has built a reputation as al Qaeda's bomb-making savant one potential near miss at a time: explosive-rigged underwear aboard a Christmas flight to the US in 2009, printers fitted with high-grade explosives less than a year later, and now possibly a metal-free device that could avoid airport detectors, causing ripples in American law enforcement agencies.
Asiri, now called 'Evil Genius', by US intelligence agencies, has emerged as CIA's worst nightmare since the slaying of terror chief Osama bin Laden and is now a major focus of America's anti-terrorism efforts, CNN reported quoting US intelligence officials.
Before those failed attempts, he staged an even more audacious attack: Turning his own brother into a suicide bomber in a mission that injured Saudi Arabia's top counterterrorism official and was later decried by the US State Department for its "brutality, novelty and sophistication."
"You tyrants ... your bastions and fortifications will not prevent us from reaching you," said an al Qaeda statement claiming responsibility for the August 2009 blast in Jiddah.
This appears to be the essence of al-Asiri's plots as one of the leaders of the Yemen-based al Qaeda in the Arabian Peninsula, or AQAP. A pattern has emerged of explosive expertise channeled into designs using a smuggler-style stealth and innovation to try to outwit security forces and spy agencies.
US authorities on Tuesday probed the latest device believed to be the work of the Saudi-born al-Asiri or one of his students after it was uncovered in a CIA operation.
It was described as a refinement of the underwear bomb that failed to detonate aboard a jetliner over Detroit on December 25, 2009. The twist this time was an absence of metal, which could have made the device undetectable by conventional airport scanners.
The primary charge in the latest device was high-grade military explosive that the Times, quoting an official, said "undoubtedly would have brought down an aircraft."
The other change in the metal-free device was that it could detonate in two ways. An improvement, to ensure that a repeat failure like the one to blow-up a jet over Detroit does not occur again.
"It was a threat from a standpoint of the design," said John Brennan, US President Barack Obama's counterterrorism adviser.
Who is al-Asiri?
Al-Asiri, 30, was a student of Chemistry in Riyah. He tried to join the al Qaeda in Iraq to fight off the 2003 US invasion but he was arrested by Saudi officials when trying to cross the border. He arrived in Yemen in 2006 after being jailed by Saudi officials in crackdowns against Islamic militants.
"They put me in prison and I began to see the depths of (the Saudi) servitude to the Crusaders and their hatred for the true worshippers of God, from the way they interrogated me," he is quoted as saying in the September 2009 issue of Sada al-Malahem, or Voice of Battles, an Arabic-language online magazine put out by al Qaeda's branch in Yemen.
His younger brother, Abdullah, also made the trek to Yemen as they turned their backs on their father, a four-decade veteran of the Saudi military.
In Yemen's rugged northern mountains, they met with fugitive Yemeni militant Nasser al-Wahishi, a former aide to Osama bin Laden, and became the nucleus of the new al Qaeda affiliate, said the magazine account, which could not be independently confirmed.
They later brought in US-born cleric Anwar al-Awlaki as a powerful propaganda voice in the West. Al-Awlaki was killed in a US airstrike last September.
US intelligence officials at first believed al-Asiri also was killed in the attack, but the suspicions were proven wrong several weeks later.
In August 2009, al-Asiri was linked to an elaborate scheme to strike at the heart of Saudi's intelligence services. His first experiment was with his brother, Abdullah, who posed as a disenchanted militant wishing to surrender to high-ranking officials in his homeland. A Saudi royal jet was dispatched. To avoid detection, the explosive- laden with 100 grams of PETN or pentaerythritol tetranitrate which was reportedly hidden in his rectum or held between his legs.
Once inside the Saudi intelligence offices in the Red Sea port of Jiddah, he detonated the device near his target: deputy interior minister Prince Mohammed bin Nayef - whose father Prince Nayef ran the ministry and would later become the kingdom's heir to the throne.
Prince Mohammed was slightly injured in the suicide blast. But for al Asiri, it was near success. Never before had they got so close to killing a royal family member.
The bomb used, was an industrial explosive known as PETN, or pentaerythritol tetranitrate, the same material used in 2001 by convicted shoe bomber Richard Reid when he tried to destroy a trans-Atlantic flight.
It would become a signature element of al-Asiri's plots, according to intelligence analysts.
After the failed Christmas 2009 bombing, investigators pulled al-Asiri's fingerprint off the bomb hidden in the underwear of the Nigerian-born suspect, Umar Farouk Abdulmutallab, aboard the Northwest Airlines flight. Click here for details.
The design of the bomb was innovative, US counterterrorism officals were quoted by CNN.
The main PETN explosive was located in a specially sewn pouch in Abdulmutallab's underwear. The explosive was connected to a detonator.
A syringe in his underwear, filled with two chemicals: potassium permanganate and ethylene glycol would serve as the inititiating device.
As the flight approached Detroit, Abdulmutallab plunged the syringe, mixing the two chemicals and setting them afire. This flame set off the detonator, according to the prosecution. The PETN device, however, failed to detonate. Instead, some of it started burning.
While those on board the Northwest Airlines Flight 253 were lucky, Asiri was undettered. Within months he designed a device that could be integrated into a printer.
Asiri was linked to the discovery of printer cartridges packed with 400 grams of PETN and sent by international courier with Chicago-area synagogues listed as the destination. Click here for details.
Specially trained dogs and even X-ray scanners could not detect the explosive-rigged packages - believed powerful enough to bring down a plane.
"The toner cartridge contains the toner which is carbon-based and that is an organic material. The carbon's molecular structure is close to that of PETN," al Qaeda in the Arabian Peninsula boasted later, reports CNN.
Asiri, a major threat?
Al-Asiri became a major focus of America's anti-terrorism efforts. In March 2011, Washington officially designed al-Asiri as a wanted terrorist, calling him the primary bombmaker for AQAP. It also presumably puts al-Asiri among the chief targets on the US hit list.
Last month, US officials expressed concern that al Qaeda "intends to advance plots along multiple fronts, including renewed efforts to target Western aviation," according to a joint intelligence bulletin circulated from the US Northern Command, the FBI and Homeland Security Department.
While al-Asiri has been dubbed the master bomb-maker of al Qaeda's Yemen franchise, it may be wrong to label him the linchpin of the group's ability to strike with explosives, said Gregory Johnsen, a Yemen expert at Princeton University.
Although US officials touted the disrupted plot as a success, they acknowledged AQAP remained determined to strike and its master bombmaker, al-Asiri, was apparently hard at work seeking to circumvent airport security.
It is al Qaeda’s affiliate in Yemen that "we're most worried about, the affiliate we spend the most time on. They're operating in the midst of essentially an insurgency, a multi-polar struggle for the control of Yemen. And that allows them the opportunity to recruit, to fundraise, to plot," say US counterterrorism officials.
"I think it is safe to assume that in the nearly six years that he has been in Yemen, he has trained other individuals to replace him if he were to be killed," Johnsen wrote on his blog on Tuesday. "It is unlikely that Asiri is the only bombmaker AQAP has within its ranks - he is just the only name we know."
Five al Qaeda leaders most wanted by US:
Ayman al-Zawahri - Egyptian cleric Ayman al-Zawahri took over the organisation, after Osama bin Laden's killing last year by Navy SEALs. Presumed hiding in Pakistan, Zawahri has released a near-record number of propaganda videos since the bin Laden raid, exhorting followers to violence.
Abu Yahia al-Libi - The Libyan militant, as his name implies, is now the group's de facto No. 2 moving up a notch in al Qaeda's hierarchy after the bin Laden raid. A key al Qaeda propagandist whose video appearances outnumber those by leader Zawahri, he escaped a high-security US prison in Bagram, Afghanistan, in 2005.
Mullah Mohammed Omar - Leader of the Taliban, Afghan Mullah Omar has sheltered al Qaeda during the Taliban rule and since. Thought to be hiding in Quetta, Pakistan, Omar continues to command the militant forces who work together with al Qaeda, responsible for killing some 1,500 US troops in Afghanistan since 2001.
Nasser al-Wahishi - Once Osama bin Laden's aide-de-camp, Wahishi commands Yemeni affiliate al Qaeda in the Arabian Peninsula, or AQAP, the group US counterterrorist officials warn is most capable of launching an attack on US soil. AQAP has established a de facto safe haven in southern Yemen, beating back Yemeni forces that have been consumed with fighting a tribal and political revolt in the wake of the Arab Spring.
Ibrahim Hassan al-Asiri - Chief bombmaker for al Qaeda in the Arabian Peninsula, responsible for building the underwear bomb used to try to bring down a Detroit-bound jetliner on Christmas 2009 and the printer-cartridge bombs intercepted in US-bound cargo planes a year later. US intelligence officials say he has resurfaced recently in Yemen, after months in hiding following the death by drone strike of American-born firebrand AQAP cleric Anwar al-Awlaki last fall.
(With various agency inputs)