A Saudi militant believed killed in the U.S. drone strike in Yemen constructed the bombs for the al-Qaida branch's most notorious attempted attacks _ including the underwear-borne explosives intended to a down a U.S. aircraft, and a bomb carried by his own brother intended to assassinate a Saudi prince.
The death of Ibrahim Hassan al-Asiri would make the Friday drone strikes on a convoy in the central deserts of Yemen one of the most effective single blows in the U.S. campaign to take out al-Qaida's top figures.
The strike also killed Anwar al-Awlaki, a Yemeni-American cleric who had been key to recruiting for the militant group and a Pakistani-American, Samir Khan, who was a top English-language propagandist.
But Christopher Boucek, a scholar who studies Yemen and al-Qaida, said al-Asiri's death would "overshadow" that of the two Americans due to his operational importance to al-Qaida in the Arabian Peninsula, the Yemen-based group that is considered the most active branch of the terror network.
Late Friday, two U.S. officials said intelligence indicated al-Asiri was among those killed in the strike. The officials spoke on condition of anonymity because al-Asiri's death has not officially been confirmed.
The 29-year-old al-Asiri was one of the first Saudis to join the Yemen-based al-Qaida branch and became its key bombmaker, designing the explosives in two attempted attacks against the United States.
His fingerprint was found on the bomb hidden in the underwear of a Nigerian man accused of trying to blow up Northwest Airlines Flight 253 over Detroit on Christmas Day 2009, according to U.S. counterterrorism officials. The attack failed because the would-be bomber Umar Farouk Abdulmutallab botched detonating the explosives, ending up only burning himself before being wrestled away by passengers.
The explosives used in that bomb were chemically identical to those hidden inside two printers that were shipped from Yemen last year, bound for Chicago and Philadelphia in a plot claimed by al-Qaida. The bombs were intercepted in England and Dubai.
In perhaps his most ruthless operation, al-Asiri turned his younger brother, Abdullah, into a human bomb in a 2009 attempt to kill Saudi Prince Mohammed bin Nayef, the kingdom's top counterterrorism official and son of its interior minister.
Abdullah volunteered for the suicide mission, asking to replace another militant named to carry it out, according to an acccount in Sada al-Malahem, an Arabic-language Web magazine issued by al-Qaida in the Arabian Peninsula. Abdullah pretended he was surrendering to Saudi authorities, and Prince Mohammed agreed to receive him in his home in Jiddah during a gathering to celebrate the Muslim holy month of Ramadan.
While talking to the prince, Abdullah blew himself up. The prince, however, escaped with only injuries.
Saudi officials have said the bomb was "inside" Abdullah's body, but explosives experts believe that al-Asiri strapped the bomb between his brother's legs.
"Come see my brother Abdullah's body parts. May he enjoy it, he was killed the way he had hoped for and his body was torn for the love of God," al-Asiri said afterward, according to Sada al-Malahem.
All three bombs contained a high explosive known as PETN, or pentaerythritol tetranitrate, which was also used by convicted shoe bomber Richard Reid when he tried to destroy a trans-Atlantic flight in 2001.
Al-Qaida in the Arabian Peninsula is led by a Yemeni militant named Nasser al-Wahishi, a former aide of Osama bin Laden, and combines Yemeni fighters with the remnants of the terror network's branch in Saudi Arabia, which was largely crushed by the kingdom's security forces in the mid 2000's. The group is believed to number several hundred fighters, hiding in the mountains of Yemen where the central government has little control.
According to Sada al-Malahem, al-Asiri and his brother Abdullah were the first of the Saudi branch to pledge allegiance to al-Wahishi, after fleeing Saudi Arabia following a month chase by Saudi authorities. After their allegiance, the magazine issued the call for other Saudi members to come to Yemen.
Al-Asiri and his brother abruptly left their Mecca home three years ago, said their father, a four-decade veteran of the Saudi military. Aside from a brief phone call to say they had left the country, he never heard from them again.
According to Sada al-Malahem, al-Asiri and his friends originally planned to go fight the Americans in Iraq, but Saudi police raided the apartment where they were hiding and arrested them.
"They put me in prison and I began to see the depths of (the Saudis) servitude to the Crusaders and their hatred for the true worshippers of God, from the way they interrogated me," the magazine quotes him as saying.
Upon his release, al-Asiri tried to create a new militant cell in Saudi Arabia but was once again discovered. Six of his colleagues were killed and he and his brother fled south to the Asir mountains where they holed up for weeks.
They entered Yemen on Aug. 1, 2006, and met with al-Wahishi, who had escaped from prison just months earlier, and became the nucleus of the new al-Qaida affiliate, said the account, which could not be independently confirmed.
AP correspondent Sarah El Deeb contributed to this report.