(CNN) Alexanda Kotey, a former ISIS fighter accused of forming one of the group's most notorious terror cells, admitted he was responsible for overseeing the imprisonment of western hostages James Foley, Alan Henning and John Cantlie.

Foley, an American journalist, and Henning, a British aid worker, were beheaded on camera by the terror group in 2014 . Cantlie's whereabouts are unknown. He was a British war photographer and correspondent before being captured by the group, and was featured as a presenter in several of ISIS' propaganda videos.

Kotey is being held by Syrian Kurdish forces in Syria awaiting potential extradition to the US. The US State Department accuses him of engaging in ISIS executions and the "exceptionally cruel torture" of Western hostages.

Speaking to the ITV News, Kotey explained that he joined ISIS as a regular fighter but was then given the job of extracting money from the hostages' families.

He added that while there was little dialogue between the fighters and hostages -- they would "speak about Islam and speak about politics" if there were ever an opportunity to talk.

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