UNITED NATIONS -- A new book that examines previously restricted files from the U.N. War Crimes Commission cites documents showing that Adolf Hitler had been indicted as a war criminal for actions by the Nazis during World War II before his death - contrary to longstanding assumptions.

The book, “Human Rights After Hitler” by British academic Dan Plesch, says Hitler was put on the commission’s first list of war criminals in December 1944, but only after extensive debate and formal charges brought by Czechoslovakia, which had been occupied by the Nazis.

The previous month the commission determined that Hitler could be held criminally responsible for the acts of the Nazis in occupied countries, according to the book. And by March 1945 - a month before Hitler’s death - “the commission had endorsed at least seven separate indictments against him for war crimes.”

Plesch, who led the campaign for open access to the commission’s archive, told The Associated Press on Tuesday that the documents show “the allies were prepared to indict Hitler as head of state, and this overturns a large part of what we thought we knew about him.”

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A Dec. 15, 1944 document submitted to the commission by Czechoslovakia accuses Hitler and five members of “the Reich government,” including his deputy Rudolf Hess and Heinrich Himmler, one of the Nazis most responsible for the Holocaust, of crimes including “murder and massacres-systematic terrorism.” A photocopy is included in the book.

The United Nations War Crimes Commission was established in October 1943 by 17 allied nations to issue lists of alleged war criminals - ultimately involving about 37,000 individuals - and examine the charges against them and try to assure their arrest and trial.

Its unrestricted records, related to more than 10,000 cases, were put online in July 2013 by the International Criminal Court after an agreement with the U.N. Three months later, then U.S. Ambassador Samantha Power announced that the restricted files - which contain some 30,000 sets of pre-trial documents submitted by national and military tribunals to the commission to judge whether a case should be pursued - would be given to the Holocaust Museum in Washington.

According to the book, legally certified documents, government transcripts and interviews with torture victims “prove beyond doubt” that the U.S. and British governments were told about Hitler’s extermination camps in the early years of World War II.

Plesch said both governments acknowledged their existence but did almost nothing to stop the mass killings.

The earliest condemnations of Nazi atrocities were made in a joint statement by the Czech and Polish governments in November 1940.

In 1942, the American, British and Soviet governments led their allies in a public declaration “that explicitly condemned Hitler’s ongoing extermination of European Jews” and the book says that condemnation was far stronger than commonly believed.

“The records overturn one of the most important accepted truths concerning the Holocaust: that, despite the heroic efforts of escapees from Nazi-occupied Europe, the allies never officially accepted the reality of the Holocaust and therefore never condemned it until the camps were liberated at the end of the war,” Plesch wrote.

“The book documents not only that the extermination of the Jews was condemned officially and publicly by the allies but that specific features of the extermination were publicized, including a favored method - lethal gas - and the central place of execution - Poland,” he said.

Plesch wrote that it was beyond the scope of the book to assess why public condemnations of the extermination of Jews aren’t prominent in public and scholarly narratives of the Holocaust.

One possibility, he said, is that “significant parts of the governments in the United States and the United Kingdom were directly opposed to doing anything to help the Jews or to support war crimes prosecutions.”

Nonetheless, he cited material from the commission’s restricted archive which shows that hundreds of German “foot soldiers of atrocity” were indicted while the Holocaust was still underway by states where the crimes took place - and it shows that these national indictments were endorsed by the War Crimes Commission up to its final meetings before it was closed in March 1948.

One chapter analyzes country-by-country the indictments that began to be made early in 1944 for anti-Jewish persecution by Germans. It includes 372 cases submitted against Germany by Poland, 110 by the Netherlands, 91 by France, 52 by Czechoslovakia, 30 by Yugoslavia, 21 by the United Kingdom, 18 by Belgium, 14 by Denmark and 12 by Greece.

The book also notes cases brought against German allies Japan and Italy.

“Ultimately thousands of soldiers were tried for war crimes after World War II,” the book says. But Plesch wrote that “the commission’s files contain indictments against thousands of Nazis who were then allowed to go free.”