He has dispatched his own brother to death, hiding a bomb on him before he crossed into Saudi Arabia to target the kingdom's chief counterterrorism official. He has tried to attack the United States three times in the past three years, building small, sophisticated and hard-to-detect devices in his workshop in the rugged terrain of southern Yemen.
Ibrahim Hassan al-Asiri, who hails from a middle-class Saudi family, is the top bombmaker for al-Qaeda's Yemen branch. Only 30 years old, he represents the CIA's worst fears: a highly skilled terrorist determined to attack the United States.
American officials believe Asiri's latest bomb was designed to be smuggled onto a US-bound aircraft last month. The non­metallic device had an advanced detonator and was superior to anything created by terrorists so far. "Asiri is an evil genius," said Rep. Peter T. King, chairman of the House Homeland Security Committee. US intelligence and law enforcement officials have said Asiri built the bombs in a bid to bring down a commercial flight near Detroit and two US-bound cargo planes.
Asiri built the "underwear" bomb worn by Umar Farouk Abdulmutallab when he tried to blow up a Northwest Airlines flight headed to Detroit on Christmas Day in 2009. A year later, Asiri built the printer-bombs that al-Qaeda placed on Chicago-bound Fedex and UPS planes.
Asiri's family hails from southwest Saudi Arabia, near the Yemeni border, the region that was home to several Sept. 11 hijackers. But nothing in Asiri's childhood suggested that he and his brother Abdullah would turn to jihad. Born in Riyadh in 1982, Asiri is the son of a Saudi military officer. Asiri studied chemistry in Riyadh, but when the US invaded Iraq in 2003, he became more radicalised, like many in the Arab world.
In Exclusive Partnership with The Washington Post.