An American aid worker that the militant group Islamic State of Iraq and Greater Syria (ISIS) said was killed in a Jordanian airstrike has indeed died, officials and her family confirmed Tuesday.

“We are heartbroken to share we’ve received confirmation that Kayla Jean Mueller has lost her life,” her parents Carl and Marsha Mueller said in a statement.

Mueller’s parents had been holding out hope that she was alive after ISIS, which had held her hostage since 2013, said she was killed during a Jordanian airstrike against the group last week. Neither her family nor U.S. officials said whether Mueller was killed in the airstrike as ISIS claimed, only that she is dead.

“Kayla represents what is best about America, and expressed her deep pride in the freedoms that we Americans enjoy, and that so many others strive for around the world,” President Barack Obama said in a statement. “Kayla Mueller used these freedoms she so cherished to improve the lives of others. In how she lived her life, she epitomized all that is good in our world. ”

Obama said the United States will “find and bring justice to the terrorists” responsible for her death, “no matter how long it takes.”

Read next: Obama Faces Challenge in Congress on ISIS War Powers

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