Investigators have pulled a fingerprint of Ibrahim al-Asiri off the bomb which was hidden in the underwear of a Nigerian man accused of trying to blow up a plane over Detroit on Christmas Day 2009, US counter-terrorism officials said.
Investigators also determined that the explosives used in that bomb are chemically identical to those hidden inside two printers which were shipped from Yemen last year, bound for Chicago and Philadelphia.
Osama Bin Laden’s death leaves al-Qaida’s core in Pakistan with a leadership vacuum, one that could make the Yemeni branch known as al-Qaida in the Arabian Peninsula even more prominent.
The Yemeni franchise had already eclipsed bin Laden’s central organisation to become al-Qaida’s leading fundraising, propaganda and operational arm.
In a eulogy to bin Laden posted online earlier this month, the group’s leader promised more violence.
“What is coming is greater and worse, and what is awaiting you is more intense and harmful,” said Nasser al-Wahishi, who once was bin Laden’s personal secretary.
Al-Qaida’s Yemen branch has become so well-known in the United States that some commentators speculated in the days after bin Laden’s death that the radical US-born Yemeni cleric Anwar al-Awlaki would succeed him.
But US officials and counter-terrorism experts say that is extremely unlikely, given his American citizenship, his relative newcomer status, his 1997 arrest in San Diego on prostitution charges and the fact that he is not even the operational leader in Yemen.
The FBI has been building cases against a number of high-profile terrorists, including al-Asiri and al-Awlaki. For now, though, there is no guarantee those cases will ever make it to a courtroom.
President Barack Obama has not indicated what he would do if a major terrorist suspect was captured abroad.