It sounds like another Holocaust horror story, if an especially gruesome one. But it is a tale that, 60 years later, has stunned Poland. For what Poles have learned recently is that the perpetrators in this case weren’t Germans, though the Nazi occupiers clearly approved the slaughter. They were Poles, the Jedwabne neighbors of the Jews. And the revelation of their role has triggered a wave of agonized soul-searching since it emerged last year in “Neighbors,” a slim, carefully researched book published in Polish by Jan T. Gross, a Polish-born New York University political scientist. A stone monument in Jedwabne attributes the killings of the Jews to the Germans. But Gross’s account leaves no doubt that this is a falsified version of history–and that the local population, as well as relatives of those who were murdered, have always known what happened. Poles are learning that they can no longer think of themselves only as victims, even if they lost one fifth of their population during World War II and prided themselves on a huge resistance movement. And Poles can no longer claim that–unlike Ukrainians, Hungarians, Lithuanians and others–they were never involved in the mass killing of Jews. “This is a tremendous shock for Polish society,” notes Leon Kieres, president of the new Institute of National Remembrance.

The controversy over “Neighbors” is already spreading across the Atlantic. Some Poles worry that the book’s publication in the United States in April will reinforce the stereotype, often held by American Jews, that Poland is a nation of anti-Semites who won’t face their country’s dark side. Or that Hitler put the death camps in Poland because of this anti-Semitism–a notion dismissed by Holocaust specialists. (“The Germans set up their concentration camps there because that’s where most of the Jews lived,” says Nazi hunter Simon Wiesenthal, referring to the more than 3 million Jews who lived in Poland.) But at a meeting with Jewish representatives in New York earlier this month, Kieres flatly asserted that the Poles were responsible for the murders and promised a full investigation.

In the late 1980s Polish intellectuals began speaking openly about the need to reassess the Holocaust. But defensiveness was far more common than openness. Poles admitted that some of their countrymen denounced Jews and that others were indifferent to their fate, but they noted that the Polish underground had tried to inform the disbelieving West about the Holocaust. And they eagerly pointed out that more Poles than any other nationality are honored at Yad Vashem, Jerusalem’s Holocaust Memorial, for saving Jews. But, as one Polish commentator put it in the current debate, the positive side of the story “doesn’t neutralize in any way our villainy.” Stanislaw Krajewski, a leader of Poland’s remaining Jewish community, praises such “impressive honesty.”

What motivated the killers in Jedwabne? In “Neighbors,” Gross speculates that they were spurred by greed as much as by anti-Semitism: they wanted to grab whatever they could from the Jews. He also points to evidence–not as well documented as Jedwabne–that similar murders occurred in nearby towns at the same time for similar reasons. But, he says, “I’ve never encountered anything else that would approximate the ferocity and scale of what happened” in Jedwabne. In 1939, when Hitler and Stalin divided Poland between them, Jedwabne came under Soviet control. When Germany attacked the Soviet Union on June 22, 1941, the town was taken over by the Germans. Rabbi Jacob Baker of Brooklyn, N.Y., who left Jedwabne in 1938 but lost 24 relatives in the massacre, agrees with Gross that plunder was the most likely motive. “The feeling was that the Germans had condemned the Jews anyhow,” he says.

Gross isn’t without his critics. Their most frequent refrain is that he underplayed the resentment many Poles felt toward Jews who had collaborated with the Soviet authorities. “That’s an anti-Semitic canard,” Gross replies. He says Jews didn’t collaborate more than non-Jews with the hated Soviet secret police. He also denies that Jedwabne epitomizes Polish behavior. “This wasn’t representative of a wider trend,” he says. But it has guaranteed that Poles will never see their wartime history in the same way.