Saudi national Khalid al-Fawwaz, a former aide of Osama Bin Laden, has been found guilty of plotting the al-Qaeda bombing of US embassies in east Africa in 1998 that killed 224 people.
Khalid al-Fawwaz, 53, was convicted by a New York court after three days of jury deliberations.
Extradited from the UK to the US in 2012, Khalid al-Fawwaz was found guilty on four conspiracy counts and now faces a possible life sentence.
Khalid al-Fawwaz has been described as Osama Bin Laden’s spokesman in London.
A statement from Preet Bharara, the US Attorney for the Southern District of New York, said the defendant “played a critical role for al-Qaeda in its murderous conspiracy against America”.
There were a dozen Americans among the dead after US embassies in Nairobi, Kenya, and Dar Es Salaam in Tanzania were bombed in 1998.
He was arrested in London in the same year as the bombings and extradited 14 years later.
Preet Bharara described Khalid al-Fawwaz as one of Osama Bin Laden’s “original and most trusted lieutenants” who was the leader of an al-Qaeda training camp in Afghanistan, then later acted as Bin Laden’s “media adviser” in London.
One of his roles, Preet Bharara said, was to ensure Osama Bin Laden’s threats against the US were distributed and noticed across the globe.
“Murderous words lead to murderous action,” assistant Attorney Nicholas Lewin told jurors.
The trial, which lasted a month under very heavy security in Manhattan, did not feature any testimony from the defendant.
When the verdict was read out, Khalid al-Fawwaz stood expressionless.
Five other people have already been convicted in New York for the embassy attacks.