The ISIS spokesman killed by Kurdish fighters in a raid with US special forces on Sunday was Abu Bakr Al Baghdadi’s right-hand man, experts said.
Syrian Democratic Forces commander-in-chief Mazloum Abdi said that Abu Hassan Al Muhajir was "targeted in the village of Ain Al Baydah near Jarablus, in a co-ordinated operation between SDF intelligence and the US army".
A top Kurdish official, who declined to be named, said that Al Muhajir was killed.
Al Muhajir became the group’s spokesman in December 2016 after the death of his predecessor, Abu Mohammad Al Adnani, in a US airstrike on Aleppo.
Little is known about Al Muhajir, who had never been seen in photographs or on video. Had he lived, he would have been a likely candidate to succeed Al Baghdadi.
His real name and nationality are not known, but his nom de guerre – The Immigrant – led to speculation that he was neither Iraqi nor Syrian.
In his role as a mouthpiece for the extremist group, Al Muhajir made several recorded audio speeches. His first in December 2016 called for attacks on Turkey and “all over the world”. In June 2017, his Ramadan speech called specifically for so-called lone wolf attacks in the US, Australia, Europe and Russia.
His repeated incitement led to a wave of attacks, analysts say.
Following attacks in March which killed 50 Muslims attending mosques in Christchurch, New Zealand, Al Muhajir released a 44-minute recording on the Telegram messaging app encouraging revenge.
"The scenes of the massacres in the two mosques should wake up those who were fooled, and should incite the supporters of the caliphate to avenge their religion," he said.
The speech was his last to be released. The last piece of ISIS territory was reclaimed later that month, nearly five years after the group's so-called caliphate was proclaimed by Al Baghdadi. Losing its territory largely reduced the organisation to scattered sleeper cells.
At the time, Al Muhajir came out of months of silence to spur on the extremists.
The group, now without a mouthpiece, has yet to confirm or react publicly to the deaths, but some fake announcements were circulated on Telegram, according to Chelsea Daymon, a terrorism researcher at the American University’s School of Public Affairs.
“Nashir News Agency [ISIS media outlet] is carrying on regardless of events, posting normal content on ISIS operations," she tweeted.
“They are taking their time with this one.”