Kayla Mueller's parents had been holding out hope.
But on Tuesday, the American ISIS hostage's family revealed devastating news.
They received it, officials said, in a message from her captors.
"We are heartbroken to share that we've received confirmation that Kayla Jean Mueller has lost her life," the family said in a statement. "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."
ISIS sent the family a private message over the weekend, National Security Council spokeswoman Bernadette Meehan said.
"Once this information was authenticated by the intelligence community, they concluded that Kayla was deceased," Meehan said.
The message sent to the family included photos. One picture showed her wrapped in a burial shroud, but there was enough showing for the family and forensics examiners to identify her, according to a U.S. official briefed on the matter.