ISIS has released a video purporting to show another hostage beheading.
The victim is Alan Henning, a British taxi driver who was kidnapped while delivering aid to Syria last December.
Henning's captors had threatened to kill him in a video from last month, which showed the execution of UK hostage David Haines.
On Tuesday, Henning's wife appealed to ISIS to spare her husband. Barbara Henning's emotion was palpable as she read from a written script: "Alan was voluntering with his Muslim friends to help the people of Syria. He was in the right place, doing the right thing. We are at a loss why those leading Islamic State cannot open their hearts and minds to the truth about Alan's humanitarian motives for going to Syria."
This story is developing and will be updated.