The video appears to have been shot in Syria. The prisoner, whose face and upper body are covered in cuts and bruises, is first made to speak to the camera 'admitting' his wrongdoings.
Speaking in Arabic, the prisoner who gives his name as Ziad Abdel'al Abu Tarek says he is from Al-Qaryatayn, a town in central Syria, and describes his work as a spy.
He concludes: 'I killed Abu Hassan and the Islamic State came and captured me.'
Last week, shocking images emerged showing decapitated bodies strewn across blood-filled streets in Palmyra, close to Al-Qaryatayn after ISIS stormed the ancient city.