Terrorism experts have raised serious doubts about whether an interview that aired on 3AW on Monday purporting to be with Islamic State military commander Omar al-Shishani was actually conducted with the Islamic State military leader.

In a lengthy interview during 3AW Drive with Tom Elliott, a man said to be Shishani dismissed atrocities committed by his troops as Western propaganda, or as actions committed against “non-Muslims”, and defended the actions of Australian jihadi Khaled Sharrouf, describing him as a “faithful man”.

But the interview, wholly conducted in English over Skype, is unlikely to be genuine, Monash University terrorism expert Greg Barton told Crikey.

Barton says he was contacted by 3AW to assess the legitimacy of the man in the interview. “The context of what he’s saying is certainly consistent with what we know,” he said. 3AW’s blog carries a statement from Barton saying as much. But upon closer examination and conferring with his colleagues, Barton no longer believes it likely that the interview was actually conducted with Shishani.

Omar Shishani, or “Omar the Chechen”, is one of IS’ leading military commanders and joined the group in Syria in 2012. He’s one of the group’s most recognisable faces, appearing often in the group’s propaganda videos. But he doesn’t appear a man fond of journalists — apart from the 3AW interview, Crikey could find no other instances of his being quoted in the English press. In videos where Shishani has been recorded, he speaks Russian or Arabic in a soft voice markedly different from the one aired on 3AW. The man interviewed by 3AW spoke English with a heavy Arabic accent. It’s not clear if Shishani speaks English at all, Barton says.

Barton adds that it’s hard to believe he would choose his first public statement to be carried by an Australian radio station, especially given the risks of staying for so long on the Skype call. “On the balance of probabilities, it’s unlikely that Shishani would choose to do an interview with 3AW. Maybe CNN or the BBC would be worth his trouble in getting his message out.”

Crikey contacted 3AW Drive yesterday and again this morning to ask whether the program still stood by its interview. We received no response before deadline, but according to this morning’s Australian, Tom Elliott told listeners to his show yesterday that he was aware of doubts about Shishani’s English-language skills.

“Prior to putting him on air, we did everything we could to establish his identity as genuine. We stand by our belief that the man … was an Islamic militant fighting for the violent overthrow of the Iraqi government and the establishment of a fundamentalist caliphate. But you just never know these days, do you?”

After the exclusive interview aired, numerous media outlets reported on the interview, including Fairfax’s websites and the Daily Mail Australia. Age editor-in-chief Andrew Holden told Crikey it was originally impossible for his journalist to check the bona fides of the man interviewed, so the newspaper wrote up the interview straight late on Monday night. “When I learned [on Tuesday] that 3AW had concerns about the legitimacy of the interview, I asked for the online story to be taken down,” Holden said.

The Daily Mail’s story remains online.

Barton says it’s possible the man interviewed was an associate of Shishani, as he was certainly across the detail of Islamic State’s military campaign.

“It was a good impulse to connect with somebody in the region,” he added. “Ten years ago, I don’t think anyone in the media would have thought of sourcing something this way. After the Arab Spring, where front-line reports from activists on the ground became common, it’s something that’s happening more and more. But of course, confirming the identity of who you’re speaking to can be fraught with difficulty.”