The US believes that Ibrahim al-Asiri, a master al Qaeda bombmaker, is dead.
The Saudi Arabian native was the mastermind behind the "underwear bomb" attempt to detonate a flight above the skies of Detroit on Christmas Day in 2009.
A senior US official expressed "confidence that he was killed."
Two US officials told CNN al-Asiri was killed by a CIA drone last year. The CIA is not commenting on his fate.
CNN reported last week that al-Asiri may have been killed in Yemen last year, according to a UN team that tracks terrorist groups.
Counterterrorism analysts say there should be significant skepticism over al-Asiri's possible demise for one major reason: His group, al Qaeda in the Arabian Peninsula, has not released any statement acknowledging his death, nor a eulogy celebrating his martyrdom.
Al-Asiri is widely credited with perfecting miniaturized bombs with little or no metal content that could make it past some airport security screening. That ability made him a direct threat to the US, and some of his plots had come close to reaching their targets in the US.
In addition to the "underwear bomb" attempt, al-Asiri was behind the so-called "printer bomb" plot. That plan saw him send explosive devices inside printers to the US. The two packages were being shipped from Yemen through Dubai and the UK in October 2010.
Both were addressed to synagogues in Chicago.
Al-Asiri appeared to have taken on a more public-facing role within al Qaeda in the Arabian Peninsula in recent years, including purportedly recording a speech the group released in 2016.
The most recent public statement attributed to him was a written speech released by the group on September 12, 2017, to coincide with the 16th anniversary of the 9/11 terrorist attacks. The speech promised an ongoing war against the United States.
CNN cannot independently verify he authored these statements.
Few expect al-Asiri's expertise to die with him. Officials believe he trained a number of apprentices. And since 2014, US officials have been concerned that bomb-making expertise built up by al Qaeda in the Arabian Peninsula has migrated to other groups, including al Qaeda operatives in Syria.
Meanwhile, ISIS is among the terrorist groups that have worked to develop laptop bombs, prompting large electronics to be temporarily banned in the cabin on certain flights to the United States and the UK from the Middle East last year.