Almost $6 million disappeared due to alleged fraud by its own employees and others, the Red Cross said on Saturday.

The disclosure comes from an internal investigation into fund expenditures from 2014 to 2016 to combat an epidemic that killed more than 11,000 people in Sierra Leone, Liberia and Guinea. The funds were going to be used to fight the Ebola outbreak in all of West Africa.

The outbreak began in Guinea and spread rapidly to Sierra Leone and Liberia. The initial international response was slow, and once the funds arrived, they were usually quickly distributed in the middle of the hustle to buy supplies and send first aid workers where they were needed.

At least $2 million disappeared due to a “probable conspiracy” between employees of Sierra Leone bank and Red Cross workers, according to the investigation.

“I am disappointed and worried about the reaction of some people, whose actions undermine the incredible work of the Red Cross staff and volunteers during the Ebola outbreak,” said Paul Jenkins, head of the delegation for the International Federation of the Red Cross and Red Crescent Societies in the capital city of Sierra Leone, Freetown.

“The actions (of the Red Cross workers) saved thousands of lives and the IFRC will continue to make sure that the funds are used for the assigned purposes,” he added.

The IFRC said it was strengthening its practices to combat corruption, including limits on cash expenditures in “high-risk places.” He also plans to send trained auditors along with their emergency operation teams. He will also have more training for his staff, “will establish an internal and independent research practice, dedicated only to this.”

The findings of the internal investigation were first reported online on October 20, but were not reported widely until Friday. The IFRC confirmed the findings on Saturday and said it was working with the Sierra Leone Anti-Corruption Commission to “investigate and bring charges against all the people involved.”