CAIRO – A Saudi militant believed killed in the US drone strike in Yemen constructed the bombs for the Al Qaeda branch’s most notorious attempted attacks – including the underwear-borne explosives intended to a down a US 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 US campaign to take out Al Qaeda’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 Qaeda, said Asiri’s death would “overshadow’’ that of the two Americans due to his operational importance to Al Qaeda in the Arabian Peninsula, the Yemen-based group that is considered the most active branch of the terrorist network.
Late Friday, two US officials said intelligence indicated that Asiri was among those killed in the strike.
The officials spoke on condition of anonymity because Asiri’s death has not been officially confirmed.
Asiri, 29, was one of the first Saudis to join the Yemen-based Al Qaeda branch and became its key bomb maker, 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, US counterterrorism officials said.
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 Qaeda. The bombs were intercepted in England and Dubai.
In perhaps his most ruthless operation, Asiri turned his younger brother, Abdullah, into a human bomb in a 2009 attempt to kill a 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 account in Sada al-Malahem, an Arabic-language Web magazine issued by Al Qaeda 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 was injured but survived.
Saudi officials have said the bomb was “inside’’ Abdullah’s body, but explosives experts believe that 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,’’ 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.
Meanwhile, Yemeni officials yesterday provided more details about their role in the tracking and killing of Awlaki, while a government spokesman said the United States should show more appreciation to Yemen’s embattled president for his assistance in the case.
A high-ranking Yemeni official who spoke on the condition of anonymity said Yemen had provided the United States with intelligence on the location of the cleric.
He said Yemeni security officials located Awlaki on Friday morning in a house in the village of Al Khasaf in Al Jawf Province. The remote village lies in a desert where the Yemeni state has no control and tribes with varying loyalties rule.
The United States said Awlaki, a propagandist for the Yemeni branch of Al Qaeda, had taken on an operational role in the organization, and last year the Obama administration placed him on a list of targets to kill or capture.
The killing came a week after the return to Yemen of President Ali Abdullah Saleh, who had been recovering in Saudi Arabia from wounds suffered in an assassination attempt. The timing of the airstrikes fueled speculation that Saleh, who has frequently portrayed himself as an essential bulwark against Al Qaeda, had handed over Awlaki in order to reduce US pressure on him to leave.