CNN reports: Peter Kassig first went to the Middle East as a U.S. soldier and returned as a medical worker, feeling compelled to help victims of war.

“We each get one life and that’s it. We get one shot at this and we don’t get any do-overs, and for me, it was time to put up or shut up,” he said in a 2012 interview with CNN.

Now Kassig, 26, is being held hostage by ISIS.

His life was threatened Friday in an ISIS video that showed the apparent beheading of British aid worker Alan Henning.