Steven Sotloff, the slain American journalist, was sold to the Islamic State by a member of a moderate rebel group, according to the Sotloff family.
In an interview with CNN, family spokesman Barak Barfi said that Sotloff's location at the Syrian border was sold for "between $25,000 and $50,000" as part of a tip-off to the militant group.
"Somebody at the border crossing made a phone call to ISIS, and they set up a fake checkpoint with many people," Barfi said. "Steve and his people that he went in with could not escape. For the first time, we can say Steven was sold at the border."
According to Barfi, Sotloff, the 31-year-old freelance journalist, was kidnapped after false rumours spread by "activists" that said he was responsible for the bombing of a Syrian hospital. This led to his abduction and sale to Islamic State militants.
"Steven's name was on a list that he had been responsible for the bombing of a hospital. This was false, activists spread his name around," said Barfi, a research fellow at the New America Foundation.
He further told CNN that the rebel group that sold Sotloff to the IS were likely part of a wider rebel group which U.S. President Barack Obama considered supporting in the hope of throwing Syrian President Bashar al-Assad from power.
"We believe that these so-called moderate rebels that people want our administration to support, one of them sold him probably for something between $25,000 and $50,000 to Isis and that was the reason he was captured," Barfi said.
Sotloff, a Miami native, was beheaded by an IS militant Sept. 2 in a videotaped execution. He was held hostage in Syria since August 2013. He worked as a journalist for Time and Foreign Policy magazines.