Tune in to ABC News' "20/20" Friday, Aug. 26, at 9 p.m. on ABC15 for the full Brian Ross report, "The Girl Left Behind."
The White House says President Barack Obama plans to donate to the foundation honoring Kayla Mueller (, an American killed by Islamic State militants last year.
A foundation in Mueller's name seeks to honor her commitment to humanitarianism and serving the needy. But Mueller's father told ABC News in an interview airing Friday that Obama promised during a private meeting in March 2015 to make a contribution, then never did.R
White House spokesman Josh Earnest says he won't discuss private presidential conversations. But he says Obama intends to contribute to the foundation in the future. Earnest says the organization is consistent with the types of charities the president and first lady Michelle Obama have donated to previously.
Earnest says the pain and grief Mueller's family is expressing is "entirely understandable."