“They knew exactly how it was done,” said a person with direct knowledge of what happened to the hostages. The person, who would only discuss the hostages’ experience on condition of anonymity, said the captives, including Foley, were held in Raqqah, a city in the north-central region of Syria.

James Foley was beheaded by the Islamic State last week in apparent retaliation for U.S. airstrikes in Iraq where the militant group has seized large swathes of territory. The group, which also controls parts of Syria, has threatened to kill another American, journalist Steven J. Sotloff. He was seen at the end of a video showing Foley’s killing that was released by the militant group. Two other Americans are also held by Islamic State.

A second person familiar with Foley’s time in captivity confirmed Foley was tortured, including by waterboarding.

“Yes, that is part of the information that bubbled up and Jim was subject to it,” the person said. “I believe he suffered a lot of physical abuse.”