American journalist James Foley was reportedly one of four hostages held by ISIS who were tortured using techniques modelled on the CIA.
Mr Foley was held captive for nearly two years before he was killed in an horrific video released last week.
A person said to be familiar with the treatment of the hostages told The Washington Post the group was held in Raqqah, a city in the north-central region of Syria.
Mr Foley was said to be one of four hostages interrogated using waterboarding.
A US official said that to suggest there was any correlation between ISIS' "brutality and past US actions was ridiculous and feeds into their twisted propoganda".
The Washington Post reports that three CIA detainees, Khalid Sheik Mohammed, Abu Zubaida and Abd al-Rahim al-Nashiri, were waterboarded.
President Obama banned the used of waterboarding on taking office in 2009.
Waterboarding is a form of torture in which water is poured over a cloth covering the face and breathing passages, causing the person to experience the sensation of drowning.