Despite the calls for violence in his videos, Abu Ghaith argued his role was a purely religious one
Osama Bin Laden?s son-in-law Sulaiman Abu Ghaith, who was an al-Qaeda spokesman after 9/11, has been convicted of terrorism-related charges at a trial in New York.
He could face life in prison when he is sentenced in September for conspiracy to kill Americans and aiding al-Qaeda.
The Kuwaiti clergyman was captured in Jordan last year and brought to the US.
He is the highest-ranking al-Qaeda figure to face trial on US soil since the attacks.
The jury returned a guilty verdict on three charges: conspiracy to kill Americans, conspiring to provide support to al-Qaeda, and providing support to al-Qaeda. The verdict came after about five hours of deliberation.
Videos showing Abu Ghaith threatening America with no end to the ?storm of airplanes? were shown to jurors, but he argued his role was a purely religious one, aimed at encouraging all Muslims to rise up against their oppressors.
He testified that Bin Laden had asked him to be al-Qaeda?s spokesman on the night of the 9/11 attacks.
On Monday, during closing arguments, Assistant US Attorney John Cronan highlighted what he said was the importance of Abu Ghaith?s post-9/11 status.
?Going to that man was the very first thing Osama Bin Laden did on September 11 after the terror attacks,? he said. ?The defendant committed himself to al-Qaeda?s conspiracy to kill Americans, and he worked to drive other people to that conspiracy.?
Denying he was an al-Qaeda recruiter, Abu Ghaith insisted he had agreed to meet with Bin Laden in a cave on the night of September 11 out of respect for Bin Laden?s standing as a sheikh.
One witness at the trial was a British man who was supposed to join Richard Reid in the attempted shoe-bomb airline attack of December 2001. The man left the plot after his parents warned him against involvement in terrorism.
He did not know Abu Ghaith, but prosecutors introduced evidence to show Abu Ghaith knew there were detailed plans for more air attacks on the US, as he promised.
Abu Ghaith?s defence lawyer, Stanley Cohen, argued there was ?zero evidence? that the 48-year-old former teacher knew of the conspiracies and warned jurors not to let prosecutors ?intimidate you and to frighten you into returning verdicts not based upon evidence, but fear?.
Abu Ghaith is married to Bin Laden?s eldest daughter Fatima.