For more about Peter Kassig’s life of service, click here.

In the months since Peter Kassig’s capture in October 2013, even as other Islamic State hostages were brutally killed, a hope glimmered. For this hostage’s name was no longer Peter. It was Abdul Rahman Kassig. He had converted to Islam — a conversion that appeared to lend his distraught parents some small card to play.

In an early October appeal, his mother, Paula Kassig, her delicate features shadowed by a hijab, read a statement that mentioned her son’s choice. “As Muslims around the world, including our son Abdul-Rahman Kassig, celebrate Eid ul-Adha, the faith and sacrifice of Ibrahim, and the mercy of Allah, we appeal to those holding our son to show the same mercy and set him free,” the parents said.

That glimmer of hope was extinguished in horrific fashion on Sunday morning with the release of an Islamic State video that showed the beheading of their son. Other men were also slaughtered, the camera lingering on their bloody corpses for long moments. It then showed Kassig’s remains beneath the militant who has come to be known as “Jihadi John.”

“This is Peter Kassig, a U.S. citizen of your country,” the killer said, declining to use Kassig’s Muslim name. “Peter, who fought against the Muslims in Iraq while serving as a soldier under the U.S. Army, doesn’t have much to say. His previous cellmates have already spoken on his behalf…. The spark has been lit here in Iraq, and its heat will continue to intensify until it will burn the rest of the crusaders. And here we are, burying the first American crusader in Dabiq, eagerly awaiting the remainder of your armies to arrive.”

It would seem intuitive for Islamic State hostages to convert to Islam in order to win some modicum of mercy from captives who proclaim profound religiosity. But it clearly doesn’t work, according to accounts and stories from Somalia to Syria. And why should it, since the Islamic State has proven itself willing to massacre people of all faiths by the thousands? The only out for a hostage seems to be ransom or escape.

Conversion to Islam appears fairly common among jihadists’ hostages. Executed journalist James Foley, who until his capture was a devout Christian and spent a prior captivity stint in prayer, converted to Islam and took the name Abu Hamza, according to a harrowing New York Times report. “I recited the Quran with him,” fellow hostage Jejoen Bontinick, 19, told the Times. “Most people would say, ‘Let’s convert so that we can get better treatment.’ But in his case I think it was sincere.” Fellow hostages Kassig and reportedly John Cantlie also converted, as well as a “majority of Western prisoners,” the Times said.

It’s impossible to determine whether someone in captivity and threatened with death converts willingly or is capable of doing so. Sometimes, such conversions are clearly forced, as was the case for Fox News reporter Steve Centanni and photographer Ola Wiig, who were captured in Gaza. (In a video declaring fealty to Islam, both men stumbled on their recitations.)

For Foley, it might have been different. “Mr. Foley had been captivated by Islam,” the Times reported. “When the guards brought an English version of the Quran, those who were just pretending to be Muslims paged through it.” But Foley, who endured perhaps the harshest torture, was consumed by it.

Other hostages, held in Somalia, also experienced horrific conditions despite their conversion. In 2008, several armed militants, faces swaddled in scarves, took Amanda Lindhout and Nigel Brennan. The hostages quickly converted. “It was a survival move and not a spiritual one, made in the hope that it might garner us better treatment,” Lindhout later wrote. “Five times a day now, prodded by the craggy voice of a muezzin calling from nearby mosque, we went through the motions of prayer…. A few of the boys spent time teaching us how to memorize verses in Arabic, so we could gain favor with Allah.”

But while those verses may have won favor with Allah, they did little to turn captors into friends. Lindhout was gang-raped, bound and beaten for days, the New York Post reported. Brennan, meanwhile, was tormented by the sounds of Lindhout’s sexual abuse.

American Theo Padnos, taken by an al-Qaeda offshoot in Syria, saw similar depravity during his captivity. He declined to convert to Islam, a stance that in his telling appeared to slowly win the respect of the jihadists. A fellow hostage, American Matt Schrier, converted to Islam. At first, the jihadists were elated at their success.

“The younger fighters would point at him and, ‘You, good!'” Padnos wrote in a New York Times Magazine piece. “Then they would point at me and say, ‘You, bad!’ But the conversion did not get Matt better food, and it certainly did not get him home.” At one point, one of the guards hit him while he was heading to the bathroom. “‘You, bad!’ he said to Matt. ‘You lie about religion.’ The guard nodded at me. ‘You, you Christian,’ he said. ‘You, good.'”

But even that token of respect was fleeting. Padnos got out much later after the Qataris helped engineer his release, following several escape attempts. Indeed, one of the greatest tragedies of any hostage crisis is the oscillating hope — hope that conversion will help, hope they’ll take mercy on you. And then, as in Kassig’s case, for that hope to disappear.