The American hostage Abdul-Rahman Kassig, known as Peter Kassig before he converted to Islam, is now a "dedicated Muslim", according to a former cellmate. The aid worker was kidnapped in Syria by the so-called Islamic State.
Abdul-Rahman Kassig, 26, always cut a slightly unworldly figure on the Turkish-Syrian border: open, honest, slightly intense, beguiled by Syria's uprising and motivated by the simple desire to help people. It didn't surprise me when his parents later spoke about him "searching for his place in the world".
He found that place giving medical training to Syrians, teaching skills that probably saved a number of lives. It was a job with many risks: bullets and bombs; air strikes and kidnapping.
"The last time I saw him," said a Syrian colleague, Dr Anas Mulla, "I asked: Aren't you scared for your life? He said: My life isn't worth more than all of yours."
Going to Deir Azour in northern Syria a year ago, Abdul-Rahman was seized by the group calling itself Islamic State. They have said he will be the next Western hostage to die.
The French journalist Nicholas Henin was held with Abdul-Rahman for four months - before being freed along with the other French hostages.
"The beginning of his detention had been a bit hard," Nicolas said of his former cellmate. "He was quite affected by his captivity."
Nicolas spoke to me in Paris. Taxis trundled by on a cobbled street outside as he described the mixture of hunger, boredom and terror experienced by the Western hostages.
"The routine was mostly waiting for food, because we never received enough. And Abdul-Rahman was basically sharing all of his food but looking for sweets. He was always looking for some extra marmalade."
Shortly after being kidnapped, Peter converted and now uses the Muslim name Abdul-Rahman.
"When I first met him, he was introducing himself already to all the guards as Abdul-Rahman," said Nicolas.
"Peter told me about how important Islam was to him, how much it helped to overcome his situation in captivity. And he was a very dedicated Muslim. He gave me the impression that he was a bit fragile, but that Islam was strengthening him."
Abdul-Rahman wasn't the only Western hostage to become a Muslim.
"In our group of hostages there were a few who converted. They were practising … the five daily prayers and they would even sometimes perform two extra prayers…They would fast on Mondays and Thursdays, which is extra [to what is mandated] … like … dedicated Muslims."
Wasn't this just Stockholm Syndrome, I asked, a perfectly understandable defence mechanism?
"Our captors were not very good at psychology," Nicolas replied. "But they were extremely good at preventing us from having any Stockholm Syndrome."
That was an elliptical reference to the stories about the hostages being beaten and even tortured.
He continued: "For some guards, there would be more respect to those of us who had converted. But for other captors, I had the feeling that it made no difference."
I asked Nicolas if he had seen the latest hostage video, the one where Alan Henning is killed, and where Abdul-Rahman Kassig is threatened with death. There was a very long pause before he told me he had seen all the videos.
"It's very traumatic for me," he said, "because I can very much imagine seeing me being in their place."
Abdul-Rahman managed to get a letter out to his family. In it, he wrote: "In terms of my faith, I pray every day and I am not angry about my situation in that sense. I am in a dogmatically complicated situation here, but I am at peace with my belief."
His parents interpret that as a statement he is now Muslim. They hope desperately that his faith will save him.
Of course, for the group that calls itself Islamic State, hostage-taking and summary executions are an everyday tactic of war.
His family must hope that "Peter Kassig" becoming "Abdul-Rahman Kassig" may help. They will also be painfully aware that Islamic State have not hesitated to kill many Muslims - Iraqis and Syrians - in the course of their bloody campaign.