Hochschild cites the research of several historians, many of them Belgian. He refers especially to Jules Marchal, formerly a Belgian colonial civil servant and diplomat who (as Hochschild describes) spent twenty years trying to break Belgian silence about the massacres. The documentation was not easy to come by; the furnaces of the palace in Brussels are said to have spent more than a week burning incriminating papers before Leopold turned over his private Congo to the Belgian nation. For many years Belgian authorities prevented access to what remained of the archives, notably the accounts given by Congolese to the King's Commission.
Although few African scholars outside Belgium seriously question that large numbers died in Leopold’s Congo, the subject remains a touchy one in Belgium itself. The country’s Royal Museum for Central Africa, founded by Leopold II, mounted a special exhibition in 2005 about the colonial Congo; in an article in the New York Review of Books, Hochschild accused the museum of distortion and evasion.
Also in 2005, the American and British publishers of King Leopold’s Ghost reissued the book with a new “Afterword” by Hochschild in which he talks about the reactions to the book, the death toll, and events in the Congo since its publication.