American aid worker Kayla Mueller - who was being held by Islamic State - has died, President Barack Obama has confirmed.
Ms Mueller's family said they were "heartbroken" at the news, and released a copy of a letter she had written in captivity.
Confirmation of Mueller's death comes days after Islamic State claimed the 26-year-old had died in a Jordanian air strike.
The US will "find and bring to justice" those responsible for Islamic State hostage Kayla Mueller's death, President Barack Obama has vowed.
Confirming the death of the 26-year-old aid worker, Mr Obama said: "No matter how long it takes, the United States will find and bring to justice the terrorists who are responsible for Kayla’s captivity and 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.
"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."
"ISIL is a hateful and abhorrent terrorist group whose actions stand in stark contrast to the spirit of people like Kayla."
Following confirmation of the US hostage's death, Kayla Mueller's family have released a copy of a letter she wrote in captivity in 2014.
Here is what we know about American aid worker Kayla Mueller who was being held by Islamic State.