A prominent Polish historian presented evidence Wednesday about Polish villagers' widespread killing of Jews fleeing Nazis during World War II, touching a raw nerve in a country still grappling with its role during the Holocaust.

The research is likely to irk the nationalist Polish government, which has taken aim at those seeking to undermine its official stance that Poles were only heroes in the war, not collaborators who committed heinous crimes.

In launching the English-language version of her 2011 book, "Such a Beautiful Sunny Day," Barbara Engelking details dozens of cases of everyday Poles raping Jewish women and bludgeoning Jews to death with axes, shovels and rocks. The book, which came out in Polish under the previous government, takes its title from the last words of a Jew pleading with peasants to spare his life before he was beaten and shot to death. It offers a searing indictment of Polish complicity that will now reach a far wider audience.

"The responsibility for the extermination of Jews in Europe is borne by Nazi Germany," she writes. "Polish peasants were volunteers in the sphere of murdering Jews."

For decades, Polish society avoided discussing such killings or denied that Polish anti-Semitism motivated them, blaming all atrocities on the Germans. A turning point was the publication of a book, "Neighbors," in 2000 by Polish-American sociologist Jan Tomasz Gross, which explored the murder of Jedwabne's Jews by their Polish neighbors and resulted in widespread soul-searching and official state apologies. ...