Parents Pledge To Honor Kayla Mueller’s Legacy

The parents of Kayla Jean Mueller have released a letter their daughter had written to them while being held by the Islamic State group.

In it, the 26-year-old aid worker said she was ``in a safe location, completely unharmed.''

Mueller also tells her parents she is ``fighting'' and has ``a lot of fight left inside.'' She writes that she is ``not breaking down'' and ``will not give in no matter how long it takes.''

Mueller traveled to the Turkish-Syrian border in December 2012 to work with several humanitarian groups. She was taken into captivity nine months later while leaving a hospital in Syria.

The White House says U.S. intelligence has authenticated a letter from the Islamic State group informing the Muellers of their daughter's death but has not been able to determine how or when she died.

In a statement, Carl and Marsha Mueller say Kayla ``lived with purpose,'' and they pledge to ``work every day to honor her legacy.''