Kayla Mueller: ISIS Hostage Had Spent Her Life Working for Others, Parents Say

— -- The female American aid worker who died while being held hostage by ISIS had spent much of her young life working internationally to help humanitarian causes, her family said today.

Kayla Mueller was captured by ISIS while working to help Syrian refugees on Aug. 4, 2013, and her family has made it clear that they plan to honor her work.

The family released a statement today just after the White House confirmed that Mueller, 25, had died. ISIS claimed that she died as part of a Jordanian air strike, but her cause of death has not been formally verified by intelligence sources.

"Kayla was a compassionate and devoted humanitarian," her family said in their statement. "She dedicated the whole of her young life to helping those in need of freedom, justice, and peace."

Mueller graduated from Northern Arizona University in 2009 "after only two and a half years," during which time she launched her school's chapters of Amnesty International and STAND, a national student group aimed at putting an end to genocide, her family said.

Between graduation and 2011, she worked in northern India as well as in areas effected by the Israeli-Palestinian conflict. She then returned to the U.S. and worked at an HIV/AIDS clinic during the day while volunteering at a women's shelter at night.

Her next international trip came in December 2011 when she worked as an au pair in France, but even that had a humanitarian element to it as she hoped that her improved language skills would help her to someday work in Africa.

At the same time, Mueller also created a blog where she wrote about different conflicts that she hoped to see resolved, touching on Tibet, Darfur and local environmental issues in Arizona.

She traveled to Turkey in December 2012 to help Syrian refugees, where she was captured by ISIS eight months later.

"We are so proud of the person Kayla was and the work that she did while she was here with us," the family said in their statement. "She lived with purpose, and we will work every day to honor her legacy."

The family -- Mueller's parents Carl and Marsha Mueller, her brother Eric and his family -- have asked that in lieu of flowers, supporters donate to causes that Mueller believed in.

The Rev. Kathleen Day, the head of United Christian Ministry at Kayla's college, said that she kept track of her while she was overseas via her blog.

"We've taken that long journey with her and we were forced to hold our breath," Day said this afternoon.

"She sounds so extraordinary [but] what was so extraordinary about Kayla is she did ordinary things in extraordinary measures," she said of Mueller's humanitarian work.

Day said that friends of the family had more detailed updates about Mueller's time in captivity, including the ways that she tried to stay positive in such harrowing circumstances.

"Kayla tried to teach the guards crafts to make origami, peace cranes," Day said, adding that she would also try exercising inside her cell and "standing on her head."

Her parents and brother did not publicly address the media aside from their statement, but two of her aunts read a joint statement from the rest of Mueller's relatives.

"Kayla has touched the heart of the world. The world grieves with us; the world mourns with us; the world wants to be more like Kayla and if that is her legacy and the footprint she leaves on the world, then that is a wonderful thing," her aunt Lori Lyon said as part of the joint statement.