(CNN) — The family of Kayla Mueller, an American woman held captive by the Islamist terror group ISIS, said Tuesday it has received confirmation that she is dead.
“We are heartbroken to share that we’ve received confirmation that Kayla Jean Mueller, has lost her life,” a statement from the family reads.
“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 family said.
On Friday, ISIS claimed that Mueller — captured in northern Syria in 2013 — had been killed in a building that was hit during a Jordanian airstrike on Raqqa, the militants’ de facto capital in Syria. At the time, ISIS offered no proof to back up its claim, other than an image of a building in rubble.
Over the weekend, ISIS sent the family a private message, National Security Council spokeswoman Bernadette Meehan said Tuesday.
“Once this information was authenticated by the intelligence community, they concluded that Kayla was deceased,” Meehan said.
The new information does not clarify how Mueller died, a law enforcement source familiar with the case said on condition of anonymity.
U.S. President Barack Obama offered his condolences to the young woman’s family.
“Kayla’s compassion and dedication to assisting those in need shows us that even amongst unconscionable evil, the essential decency of humanity can live on,” Obama said in a statement released by the White House Tuesday.
President Obama has spoken with Mueller’s family, Meehan said.
“He committed that we will relentlessly pursue the terrorists responsible for Kayla’s captivity and death, and underscored that his team stands ready to help the family in the difficult weeks and months ahead,” she said.
Mueller’s relatives on Tuesday also released a handwritten letter that they say she wrote while in captivity in spring 2014.
“It’s hard to know what to say,” the letter reads. “Please know that I am in a safe location, completely unharmed + healthy (put on weight in fact); I have been treated w/the utmost respect + kindness.”
Taken hostage in 2013
Mueller fell into the hands of hostage-takers in August 2013 in Aleppo, Syria, her family said, after leaving a Doctors Without Borders hospital.
Her family said ISIS contacted them in May with proof that she was alive. The militants eventually said they would kill her if the family didn’t pay nearly $7 million by August 13, 2014, according to a source close to the family. What happened after that deadline is unclear.
A life serving others
Mueller, 26, made it her life’s work to help others. After graduating from Northern Arizona University in 2009, she worked with humanitarian groups in northern India, Israel and Palestinian territories, a family spokeswoman said. In Israel, she volunteered at the African Refugee Development Center.
Mueller went back to Arizona in 2011, volunteered in a women’s shelter and worked at an HIV/AIDS clinic, helping to facilitate events and providing local coordination for World AIDS Day, the family spokeswoman said.
After working for a year as an au pair in France, she traveled to the Turkish/Syrian border to work with the Danish Refugee Council and the humanitarian organization Support to Life, which assisted families who had been forced to flee their homes due to the civil war in Syria, the spokeswoman said.
In a YouTube video produced in October 2011, before the rise of ISIS, Mueller said she supported a sit-in that protested the Syrian regime.
“I am in solidarity with the Syrian people,” she said. “I reject the brutality and killing that the Syrian authorities are committing against the Syrian people.”
Remember her work
Sen. Lindsey Graham, R-South Carolina, said Mueller should be remembered for her incredibly altruistic work, not for how she died.
“Her family’s got to be heartbroken, but my God, this is the best example, this young lady, of being an American, being a decent human being that one could imagine. I believe very strongly she is in God’s hands,” he said on CNN Tuesday.
“Those who captured her, and in my view, killed her — I think God will judge them differently.”
U.S. Rep. Paul Gosar, a Republican from Mueller’s home state of Arizona, said it feels like a “very, very sad day.”
“Here’s a beautiful girl, young person that gave her life to helping others,” he said. “I hope everybody will reach out to their respective religions with thoughts and prayers on behalf of Kayla and her family.”