DAKAR, Senegal (AP) — Red Cross officials say nearly $6 million meant to help fight the Ebola outbreak in West Africa went missing because of suspected fraud.

In one instance, an internal investigation found "likely collusion" between bank employees and former staff of the International Federation of Red Cross and Red Crescent Societies. A statement says as much as $2 million was lost.

The IFRC says it is working with Sierra Leone's Anti-Corruption Commission to "investigate and legally pursue any persons involved."

Other investigations revealed suspected fraud in the two other hardest-hit countries during the 2014-2016 epidemic. In Guinea, at least $1 million disappeared because of fraudulent billing practices by a customs clearance service provider. Two other investigations there are pending.

More than 11,000 people died during the world's worst Ebola epidemic.