The parents of Kayla Mueller, an aid worker kidnapped by the Islamic State militant group in Syria who died in captivity at age 26 in 2015, said of the U.S. raid that killed Abu Bakr al-Baghdadi that they are glad the "evil person is gone."

Carl and Marsha Mueller spoke to "Today" in an exclusive interview Wednesday with Savannah Guthrie.

The United States named the military operation that killed al-Baghdadi after Mueller, who was abducted after leaving a Doctors Without Borders hospital in Aleppo, Syria, in 2013. The native of Prescott, Arizona, was held in captivity for 18 months, including a period in which she was reportedly raped and forcibly married to ISIS leader al-Baghdadi. She was killed in 2015.

U.S. officials attempted to rescue Mueller and other ISIS hostages in 2014 to no avail.

Mueller’s family learned their daughter was killed in February 2015, but the circumstances surrounding her death have remained unclear.

Mueller’s parents spoke directly with President Donald Trump after al-Baghdadi's death was announced, pressing the president to help them get more information about their daughter, including where she is buried, they said.

National security adviser Robert O'Brien told "Meet the Press" on Sunday that the chairman of the Joint Chiefs of Staff named the operation that took down al-Baghdadi after Mueller, "after what she had suffered."

"I’m glad that evil person is gone," Carl Mueller said of the ISIS leader. "If you were a parent and this man did what he did to Kayla to your child, and then they got him, how would you feel?”

The Muellers expressed deep gratitude for the raid. "I’d like to thank those brave soldiers and everyone involved in that raid, and compliment the president on that successful mission," the father said.

Marsha Mueller said when she and her husband learned that the raid was named after their daughter, they both cried. "That was just an amazing gift for Kayla," she said. "Kayla would say this was for all of us."

"I want people to see the light in Kayla. In such utter darkness, there was light," the mother said of her daughter's time in captivity.

The Muellers also spoke of their sliver of hope that their daughter might still be alive, which they called a "one percent chance."

Carl Mueller said authorities based confirmation of her death on an announcement from ISIS and from photographs.

"We just decided it was our mission ... until she's home, we've got to find her," and find out what happened to her, Marsha Mueller said.