By Desiree Salas (media@latinospost.com) | First Posted: Nov 17, 2014 04:45 AM EST

Extremist group ISIS is back on international headlines after it was confirmed that it had beheaded yet another hostage.

"President Barack Obama on Sunday confirmed the murder of U.S. aid worker Peter Kassig by militant extremist group ISIS," Time reported. "A former U.S. Army Ranger, 26-year-old Kassig was working as a medical aid to Syrians escaping civil war when he was captured in Syria in October of last year."

The American had since converted to Islam during his captivity and adopted the name Abdul-Rahman.

President Obama had said that the recent killing was "an act of pure evil by a terrorist group that the world rightly associates with inhumanity," Reuters noted.

Meanwhile, the parents of the 26-year-old, Ed and Paula Kassig, issued a statement regarding the murder: "We are heartbroken to learn that our son, Abdul-Rahman Peter Kassig, has lost his life as a result of his love for the Syrian people and his desire to ease their suffering. Our heart also goes out to the families of the Syrians who lost their lives, along with our son."

The beheading was announced by ISIS via a video which "appeared on a jihadist website and on Twitter feeds used by Islamic State," the news source said. While the clip didn't show the actual beheading of the American worker, it showed "a masked man standing with a decapitated head covered in blood at his feet." The same man, who spoke English with a British accent, announced that the body is of Peter Edward Kassig.

Last month, it was reported that Kassig told his parents his time "is running out" in letters sent during his captivity, The Guardian said.

"They tell us you have abandoned us and/or don't care but of course we know you are doing everything you can and more. Don't worry Dad, if I do go down, I won't go thinking anything but what I know to be true. That you and mom love me more than the moon & the stars," read one of his letters to his parents.

"Physically I am pretty underweight but I'm not starved, & I have no physical injuries, I'm a tough kid and still young so that helps," Kassig also wrote. "Mentally I am pretty sure this is the hardest thing a man can go through, the stress and fear are incredible but I am coping as best I can. I am not alone."

Despite his mother's plea for his release, and the fact that a "senior al-Quaeda jihadist" had spoken out in defense of Kassig's being next in line for execution, as noted by The Telegraph, the Muslim convert still was beheaded by the ISIS.

Kassig is the fifth Western captive killed by the extremist group.