Alexandria (United States) (AFP) - The mother of slain American journalist James Foley said Monday at the trial of one of his alleged Islamic State captors that she initially hoped reports her son had been executed were "some cruel joke."

"I didn't want to believe it," Diane Foley testified at the trial of El Shafee Elsheikh, 33, who is charged with the murders of James Foley and three other Americans in Syria.

"It just seemed too horrific," Foley said. "I was hoping it was just some cruel joke."

Foley said it sank in later that day when US president Barack Obama went on television to confirm that James had indeed been executed by his IS captors.

Elsheikh, a former British national, is accused of involvement in the murders of Foley, Steven Sotloff, who was also a journalist, and aid workers Peter Kassig and Kayla Mueller.

Diane Foley, who worked tirelessly to try to obtain her son's release, said James, a seasoned combat reporter, left for Syria in October 2012 and promised to be back for Christmas.

The family began to worry when he did not call in November on Thanksgiving.

"Jim always called us on the holidays," she said. "There was a deafening silence when we did not hear from him."

She said the family was informed by a colleague of James that he had been kidnapped.

"Those first nine months, we didn't know if Jim was alive or not," she said.

The first tangible proof that James was alive came when his captors provided emailed answers to three questions that only he would know.

'Ridiculous' demands

Michael Foley, 46, James's younger brother, also testified on Monday and told the court the kidnappers never engaged in any serious negotiations.

At one point, he said, they asked the Foleys to "pressure the government to release Muslim prisoners."

They then asked for a ransom of 100 million Euros.

"This was as ridiculous as the previous one," he said. "There was no ability to secure either of those demands."

There were no communications from the kidnappers from December 2013 to August 2014, when the Foleys received a threatening email.

It warned that James would be executed in retaliation for a US bombing campaign against the Islamic State.

He was killed several days later in a gruesome video that was released on the internet.

Michael Foley said he was also informed of his brother's death in a call from a journalist seeking reaction.

He said he went online and watched the video of his brother in an orange jumpsuit and the knife-wielding IS executioner known as "Jihadi John."

"I watched it once or twice," he said. "I haven't seen it since but it's burned into my brain."

Elsheikh was allegedly a member of the notorious IS kidnap-and-murder cell known to their captives as the "Beatles" because of their British accents.

The group abducted at least 27 people in Syria between 2012 and 2015, including a number of European journalists who were released after ransoms were paid.

Videos of the brutal executions of Foley, Sotloff and Kassig were released by IS for propaganda purposes. Mueller was reportedly handed over to IS leader Abu Bakr al-Baghdadi, who allegedly raped her repeatedly before killing her.

Elsheikh and another former British national, Alexanda Amon Kotey, were captured in January 2018 by a Kurdish militia in Syria while attempting to flee to Turkey.

They were turned over to US forces in Iraq and flown to Virginia in October 2020 to face charges of hostage-taking, conspiracy to murder US citizens and supporting a foreign terrorist organization.

Kotey pleaded guilty in September 2021 and is facing life in prison. Under his plea agreement, Kotey will serve 15 years in jail in the United States and then be extradited to Britain to face further charges.

"Beatles" executioner Mohamed Emwazi was killed by a US drone in Syria in November 2015, while the fourth member of the cell, Aine Davis, is imprisoned in Turkey after being convicted of terrorism.

Elsheikh has denied the charges, and his lawyers claim his arrest is a case of mistaken identity. He faces life in prison if convicted.