As rebels set about freeing those imprisoned by the reposed Assad regime, more missing people are being found.
Earlier on Wednesday, a man who said he was locked up after crossing into Syria by foot seven months ago was found safe.
There were initial suspicions it could have been missing US journalist Austin Tice, who went missing in Syria in 2012, but he and the reporter’s family have confirmed otherwise.
Syria latest as commander warns ISIS coming out of hiding
Meanwhile, the whereabouts of a British journalist taken hostage in Syria in the same year also remain unknown, despite the British government previously claiming he is alive in 2019.
John Cantlie has appeared in videos for ISIS and is thought to be the last known British hostage held by the extremist group.
He was abducted in November 2012 with Jim Foley, an American journalist beheaded by British IS member Mohammed Emwazi – “Jihadi John” – who was himself killed in a US drone strike in 2015.
Until 2016, he fronted several English-language propaganda videos for his captors – an IS move condemned by journalism advocates Reporters Without Borders.
John Cantlie in a video released by IS
“ISIS has been using him for propaganda purposes in Syria and Iraq for the past two years,” the group’s former chief Christophe Deloire said in 2016.
“His detention and exploitation amount to unspeakable acts of torture.”
He hasn’t been heard from since.
In one video in 2016, he was pictured looking thin in the face and would talk about damage to infrastructure he said the West had caused.
He went on to say ordinary people were badly affected and “stopped in their tracks by the bombs that have destroyed these bridges”.
Later in the video, Mr Cantlie moved to another location. Behind him were people filling containers with water from a standpipe.
“Since the coalition began dropping bombs in earnest on this city, water is now a big problem,” he said.
In 2019, then security minister Ben Wallace said he was still alive in a briefing to journalists in London, though he gave no further details.
Read more:
Inside Syria’s notorious Sednaya prison
Kurdish US-allies halting anti-ISIS operations
A social media account that had been set up by supporters posted a message in response to Mr Wallace’s comments.
“We are aware of the current news circulating that John Cantlie is alive, whilst this is not substantiated at present, we continue to hope and pray that this turns out to be true,” the account, which was called Free John Cantlie, stated.
A few weeks before Mr Wallace’s claim, an official with the US-backed Syrian Democratic Forces, which had been working to take back the final pockets of IS-held territory, said Mr Cantlie might still be alive.
They added he could be in the area of Hajin, a town in the eastern Syria province of Deir Ezzor.