American hostage Abdul-Rahman Kassig also known as Peter Kassig captured by Islamic State (IS) militants a year ago has said in a recent letter to his parents that 'the stress and fear are incredible' in captivity.
According to the BBC, Kassig's parents have released more extracts of a letter written by their son in IS captivity.
Earlier the former U.S. army ranger had written that he was 'afraid to die' and was saddened by the pain his ordeal was causing his family.
Kassig's parents had also received a threat by IS extremists that their son would be beheaded.
The parents, Ed and Paula Kassig had said in a statement that a former hostage had told them that their son Peter Kassig had voluntarily converted to Islam last year when he had shared a cell with a Syrian Muslim.
Kassig was taken into captivity on October 1, 2013 while he was working as an aid worker.