Doctors Without Borders refused to negotiate American hostage Kayla Mueller's release from ISIS

Humanitarian group Doctors Without Borders refused to negotiate with ISIS for American hostage Kayla Mueller even after she helped install equipment for the organization's hospital in Syria, and was kidnapped together with other members of the MSF staff in August 2013, the victim's family has revealed.

Doctors Without Borders, also known by the name Médecins Sans Frontières (MSF), declined communication with the victim's family and was said to have withheld information critical to negotiations for Mueller's situation. 

Ten months after the kidnapping, Marsha and Carl Mueller, the victim's parents, were able to speak with an MSF senior officer to ask for help. The officer said the group's crisis management team would be closed down because MSF's kidnapped staff members were already released. The Muellers were able to record the phone conversation and shared it with ABC News.

Carl said in an interview with ABC News' "20/20," "They're a fabulous organization, and they do wonderful work, but somewhere in a boardroom, they decided to leave our daughter there to be tortured and raped and ultimately murdered."

ISIS claims the young American reportedly died in an airstrike on Feb. 6, 2015, however, this has been denied by U.S. military leqaders. Mueller was said to have suffered torture and rape while she was a hostage.

MSF U.S. executive director Jason Cone said to ABC that the organization was not obligated to help the girl because she was not actually part of the staff.

"I don't think there was a moral responsibility. We can't be in the position of negotiating for people who don't work for us," he said.

Cone added that Mueller volunteered to go to Syria and they would not have permitted her to go had they been informed that she was American.

ISIS released seven MSF staff members who were held hostage after negotiating ransom payments. The group, however, did not include Mueller in their talks with the Islamic terrorist group. They also reportedly refused to speak with the FBI agent handling the Mueller case.