She probably thought her anti-Israel activism would save her from jihadist cavemen. Sadly for her, she was wrong.

Via News.au:

COUNTER-TERRORISM officials believe an American aid worker kidnapped by Islamic State militants in August 2013 may have been married off to an ISIS commander during her captivity.
According to the jihadist group, Kayla Mueller was killed last Friday when Jordanian bombs rained down on northern Syria, flattening a building where she had been housed.

The US has limited intelligence on Syria and is forced to rely on drones and satellites for surveillance. Most of the time they had no idea of Ms Mueller’s whereabouts but occasionally her name would be overheard in phone calls between fighters, or a sensitive site was mentioned that indicated she was still alive.

There were also sightings of Ms Mueller in the company of an ISIS commander who was under surveillance. He appeared to have custody over her, possibly as a result of forced marriage, another official told ABC. She had also been seen alone.

In a heartbreaking letter written last year and released by her family today, Ms Mueller said she was “in a safe location, completely unharmed (and) healthy. I have been treated with the utmost respect (and) kindness”.

Over the weekend, Ms Mueller’s parents, Carl and Marsha Mueller, were emailed at least three photographs showing their deceased daughter. The correspondence has since been authenticated.

Two of the photographs showed Ms Mueller wearing a black Muslim head covering and another showed her wrapped in a white burial shroud, the New York Times reported.

Injuries to her face were clearly visible but it is not yet known if they are consistent with a bomb attack, as ISIS claims.