Through his clips on Youtube and other social media, Abu Daoud was the person who inspired Rakhmat Akilov to join the Islamic State. He has been assumed dead for a few years. But after a TV team was allowed to come in and film inside a prison in Syrian Afrin, it seems that Abu Daoud is still alive.

One of those who could directly identify Abu Daoud as one of the men in the Syrian prison was Sirojiddin Tolibov. He is the editor-in-chief of Radio Free Europe's Tajik department and specializes in militant Islamists from Central Asia.

"We recognized him at once and then contacted his mother and mother-in-law who confirmed that it was Abu Daoud," Sirojiddin Tolibov told SVT.

Imprisoned in eastern Syria

According to Sirojiddin Tolibov, the other man, Abu Usama Nuraki, is also alive and imprisoned in Dayr az-Zawr, a city in eastern Syria.

On Thursday, TV4 News reported that a third man with links to Rakhmat Akilov was imprisoned in Syria. The man is said to have given Akilov information on bomb manufacture before the deed.

See more from the interview with Sirojiddin Tolibov in the clip above.