The Red Cross has confirmed that more than $5m (£3.8m) of aid money was lost to fraud and corruption during the Ebola epidemic in West Africa.
Auditors found overpriced supplies, salaries for non-existent aid workers and fake customs bills.
The disease, which raged between 2014 and 2016, claimed at least 10,000 lives.
It required a massive humanitarian operation costing hundreds of millions of dollars to bring it under control.
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As Ebola spread across Liberia, Sierra Leone and Guinea, the Red Cross Federation in Geneva was dispersing cash donations to the national Red Cross societies in each of those countries - altogether a sum of about $100m.
Fraud involving donor money is every aid agency's nightmare, our correspondent says.
The Red Cross is the world's best-known humanitarian organisation, and this revelation will be damaging, she adds.