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.
US hostage Kayla Mueller was killed by Islamic State - not in a Jordanian air strike as the group previously claimed, the Pentagon said.
Asked if there was any doubt who killed the 26-year-old aid worker, Rear Admiral John Kirby replied: "No doubt. ISIL."
He added that intelligence officers were still unsure the exact cause of Ms Mueller's death.
A senior US official earlier told NBC News that IS had sent Mueller's family a photograph of her body.
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.