According to Simon Wiesenthal,
Long before the ZDF TV network, historian Gitta Sereny wrote in her 1974 book Into that Darkness, based on interviews with the former commander of the extermination camp at Treblinka, Franz Stangl, that ODESSA had never existed. She wrote: "The prosecutors at the Ludwigsburg Central Authority for the Investigation into Nazi Crimes, who know precisely how the postwar lives of certain individuals now living in South America have been financed, have searched all their thousands of documents from beginning to end, but say they are totally unable to authenticate 'Odessa.' Not that this matters greatly: there certainly were various kinds of Nazi aid organisations after the war—it would have been astonishing if there hadn't been."
In his interviews with Sereny, Stangl denied any knowledge of a group called
Sereny attributed the fact that SS members could escape more to postwar chaos and the inability of the Catholic Church, the Red Cross and the American military to verify the claims of people who came to them for help than to the activities of an underground Nazi organisation. She identifies a Vatican official, Bishop Aloïs Hudal, not former SS men, as the principal agent in helping Nazis leave
Uki Goñi, in his 2002 book The Real Odessa: Smuggling the Nazis to Perón's Argentina suggests that Sereny's more complex, less conspiratorial, story is closer to the real truth. The book prompted a US House of Representatives resolution in 2003, urging Argentina to open their hitherto secret documents concerning this matter.
Of particular importance in examining the postwar activities of high-ranking Nazis is Paul Manning's book Martin Bormann: Nazi in Exile (Lyle Stuart, Inc., 1980, ISBN 0-8184-0309-8, also available online), which details Martin Bormann's rise to power through the Nazi Party and as Hitler's Chief of Staff. During the war, Manning himself was a correspondent for the fledgling CBS News along with Edward R. Murrow and Walter Cronkite in London, and his reporting and subsequent researches present Bormann's cunning and skill in the organization and planning for the flight of Nazi-controlled capital from Europe during the dimming years of the war (notwithstanding the possibility of Bormann's death in Berlin on May 1, 1945).
According to Manning, "eventually, over 10,000 former German military made it to South America along escape routes
From December 2002, the Argentine government in Buenos Aires refused calls from the Wiesenthal Center for the release of 58 files dealing with the escape of national socialists to
Also, Argentina's government had, in 1938 (on the verge of World War II, and with Hitler's politics regarding Jews already on the move), sanctioned an immigration law restricting access to any individual scorned or forsaken by his country's government. This was implicitly targeted for Jews and other minorities fleeing Germany at the time. This law was discovered and denounced by writer Uki Goñi. This legislation, though already in disuse for many years, was finally vetoed on 8 June 2005.
The Real Odessa: How Peron Brought the Nazi War Criminals to Argentina