Adam Gadahn, who faced treason charges in the US, was killed early this year in a strike on an al-Qaeda camp in Pakistan, near the Afghan border.
“He was highly important. He was the man on their media front line,” said Ahmed Rashid, a Pakistani author and expert on the Taliban and al-Qaeda.
“Given the success of Isis in media and social media, he would have been much needed, especially in communicating with English-speaking audiences and on websites and so on.”
Gadahn, for whom the US had offered a reward of $1m, was believed to be in his late 30s. Born in Oregon, he grew up in California, converted to Islam at 17, and became a spokesman and translator for al-Qaeda.
When the US accused him of treason in 2006, he became the first person to face such charges since the era of the Second World War.
Gadahn has been involved with al-Qaeda’s as-Sahab media wing and had appeared in its videos wearing robes and a turban and warning the US it would face attacks if it did not heed al-Qaeda demands.
“He was the main man in charge of the al-Qaeda narrative, so his death will have an impact on the propaganda machine,” said Amir Rana, author of a book on militant groups in Pakistan.
Officials said Gadahn was killed five days after a US drone strike in January targeting an al-Qaeda compound in Pakistan inadvertently killed an American and Italian who had been held hostage for years by the group. Gadahn was in another al-Qaeda camp.
A Pakistani Taliban militant said Gadahn’s comrades had urged him to leave the area because of the danger of US drone strikes. “When most senior Arab commanders were killed and others left for their native countries, some people advised him to shift to a safer place but he refused.”
Gadahn, born in a Jewish-Christian family, grew up on a goat ranch outside Los Angeles, and moved to Pakistan after his conversion. He was previously known as Adam Pearlman.