WATCH: Friends of Peter Kassig were shocked to see him being held hostage by ISIS but they remain hopeful he will be rescued
ISIS appears to have killed a second foreign aid worker, a person who gave up his life to help Syrians, and has threatened to kill another.
At the end of a video appearing to show the beheading of British aid worker Alan Henning, posted on YouTube Friday, a masked-militant warned U.S. aid worker Peter Edward Kassig would be next.
WATCH: Ed and Paula Kassig made a plea for their son’s life and spoke of his humanitarian work in Syria.
CNN profiled Kassig, from Indiana, in 2012 while he was working at a hospital in Tripoli, Lebanon.
“I am not a doctor. I am not a nurse. But I am a guy who can clean up bandages, help clean up patients, swap out bandages, help run IVs, make people’s quality of life a little bit better,” he told CNN. “This is something for me that has meaning, that has purpose.”
According to the Washington Post, he joined the U.S. Army in June 2006. He was honorably discharged for medical reasons in Sept. 2007, but during his time as an Army Ranger he was deployed to Iraq — between April and July 2007.
He went on to study political science at Indiana’s Butler University, but took a break in 2010 to train to become an emergency medical technician, CNN reported.
In 2012, he travelled to Lebanon while on spring break from Butler University because he wanted learn more about the war in Syria.
He told CNN he “learned enough to know that I didn’t know anything.” He travelled back to Lebanon after he finished his semester and went to work in a hospital in Tripoli, helping who he could —some were Syrian civilians, some were Syrian rebel fighters.
When TIME interviewed him in January 2013, Kassig, now 26, said he couldn’t imagine doing anything other than helping people in need, detailing the work of the NGO he founded.
“I designed Special Emergency Response and Assistance around a belief that there was a lot of room for improvement in terms of how humanitarian organizations interact with and cooperate with the populations that they serve,” he told TIME. “SERA is focused on the distribution of aid materials to populations with an acute and immediate need. We administer aid in the form of food and cooking materials, medical supplies, and clothing.
“In five years, I certainly hope to have seen SERA grow into an international relief organization capable of helping hundreds of thousands of people around the world,” he told TIME. “I would also like to be able to say that I was able to give something back to everyone who helped along the way.”
Kassig was captured in October 2013. His parents said he converted to Islam while in captivity and now goes by the name Abdul-Rahman.
The deaths of Henning, a taxi driver back in the U.K. who joined a Muslim-led aid group in hopes of helping Syrians displaced by the war, and another British aid worker, David Cawthorne Haines, were in retaliation for British involvement in the U.S.-led international coalition formed to deal with the threat of ISIS.
Henning, was taken captive on Dec. 26 while travelling with an aid convoy from Turkey into Syria. His apparent death came three weeks after ISIS murdered Haines.
With files from The Associated Press