The family of American ISIS [Daesh] hostage Kayla Jean Mueller today confirmed her death.
'We are heartbroken to share that we've received confirmation that Kayla Jean Mueller, has lost her life,' her parents Carl and Marsha Mueller and brother Eric Mueller said in a statement on Tuesday.
'Kayla was a compassionate and devoted humanitarian. She dedicated the whole of her young life to helping those in need of freedom, justice, and peace.'
The White House also released a statement on Tuesday confirming the young woman's death.
'On behalf of the American people, Michelle and I convey our deepest condolences to Kayla’s family – her parents, Marsha and Carl, and her brother Eric and his family – and all of those who loved Kayla dearly,' the statement read. 'At this time of unimaginable suffering, the country shares in their grief.'
Mueller, 26, from Prescott, Arizona, is understood to be the last U.S. hostage held by the extremists who were demanding $6.6 million for her release.
Miss Mueller, who graduated from Northern Arizona University in Flagstaff, appears to have been committed to helping those most in need since she was a teenager.
She volunteered for three years with the Save Darfur Coalition, battling genocide in the war-torn African region.
Her parents, Marsha and Carl Mueller, who are both in their early 60s, have a large, detached hillside home in a rural area of Prescott. Mr Mueller runs an auto-body repair shop.
Miss Mueller graduated from Prescott's Tri-City College Prep High School in 2007.
From a young age, Kayla was passionate about global affairs and other cultures, working to raise awareness of the genocide in the Darfur region of Sudan in rural Arizona.
The young humanitarian conducted two silent protest marches in her hometown to raise awareness surrounding the issue in 2007.
She also wrote letters and placed calls to members of Congress to push for a change in U.S. policy. Her efforts landed her with several youth awards and she went on to dedicate her life to humanitarian aid.
As a teenager, she gave an interview to her local newspaper, The Daily Courier, where she said: 'I always feel that no matter how much I give, I always get back more through these projects.'
Miss Mueller's home town of Prescott has seen its own share of tragedy, when the area lost 19 elite 'Hotshot' firefighters in a ferocious wild fire in 2013.
The 26-year-old aid worker disappeared in August 2013 after she had driven into the Syrian city of Aleppo with her Syrian boyfriend.
In May of that year, she had been at home in Prescott, where she shared stories from the front-line with a club where her father is a member.
She told the Kiwanis Club of Prescott that she had reunited a man with a six-year-old relative after their refugee camp in Turkey was bombed, The Daily Courier reported.
In July 2013, Miss Mueller posted a verse by Persian poet and Islamic scholar on social media, which read: 'Who looks out with my eyes? What is the soul?/I cannot stop asking./If I could taste one sip of an answer, I could break out of this prison for drunks./I didn't come here of my own accord, and I can't leave that way./Whoever brought me here, will have to take me home.'
The following month, she was working at a hospital when she was taken hostage by the brutal extremists, according to reports.
Miss Mueller's family later received proof-of-life evidence as well as a ransom demanding millions of dollars - to be paid by mid-August.
The young woman was reportedly shown in a video, covered by a burqa and begging for her life.
Earlier this week, ISIS released a video of a Jordanian pilot being burned alive.
The horrific death of Muath al-Kasasbeh provoked Jordan to engage in heavy rounds of airstrikes after vowing to destroy ISIS.
Miss Mueller allegedly died during an hour-long bombardment on the jihadis' north Syrian stronghold of Raqqa, according to an unverified statement on a website commonly used by the terror group.
There were no images of Miss Mueller herself and ISIS' claim could not be independently verified. Her death could easily be a propaganda move by the terror group to lay blame for the woman's death at the door of Jordan.
In a statement to NPR radio station in the U.S., Miss Mueller's family described her as someone who was recognized for her academic abilities and her commitment to philanthropy.
It read: 'Kayla has spent her adult life traveling the world and helping those in need.
'After graduating from college, she spent more than one year living and working with humanitarian aid groups in northern India, Israel and Palestine.
She returned home to Arizona in 2011, and worked for one year at an HIV/AIDS clinic while volunteering at a women's shelter at night.
'In December 2011, she traveled to France to be an au pair so she could learn French in preparation for work in Africa.
'War sidetracked Kayla's Africa plans as she was drawn to alleviate the suffering of Syrian refugees.'
According to her family, Miss Mueller moved to the Turkish/Syrian border in December 2012 and began working with Support to Life and the Danish Refugee Council to help people who had been forced to flee their homes.
'Kayla found this work heartbreaking but compelling; she was extremely devoted to the people of Syria,' her family added.
American officials said they were looking into the reports of Miss Mueller's death. The White House did not have immediate comment.
If her death is confirmed, the Arizona native would be the fourth American to die while in the captivity of the Islamic State militants.
ISIS has executed five British and American aid workers and journalists in recent months.
Nicolas Henin, a French journalist who was held hostage by ISIS, had been held hostage with Miss Mueller. Mr Henin was freed in April 2014 after the French government negotiated with ISIS.
Mr Henin tweeted on Friday: 'Kayla Mueller was among the very last of my former cellmates still detained. I was full of hope she could have a way out.'
He refused to comment further on the 26-year-old American.
