The revelation that a top former commander of a Nazi SS-led military unit has lived quietly in Minneapolis for the past six decades came as a shock to those who knew 94-year-old Michael Karkoc.

World War II survivors in both the United States and Europe harshly condemned the news, and prosecutors in Poland have said they’ll investigate.

An Associated Press investigation found that Karkoc served as a top commander in the Ukrainian Self-Defense Legion during World War II. The unit is accused of wartime atrocities, including the burning of villages filled with women and children.

“I know him personally. We talk, laugh. He takes care of his yard and walks with his wife,” his next-door neighbor Gordon Gnasdoskey said Friday. Gnasdoskey, the grandson of a Ukrainian immigrant himself, said he was disturbed by the revelations about his longtime neighbor.

“For me, this is a shock. To come to this country and take advantage of its freedoms all of these years, it blows my mind,” he said.

Karkoc told American authorities in 1949 that he had performed no military service during World War II, concealing his work as an officer and founding member of the legion and later as an officer in the SS Galician Division, according to records obtained by the AP through a Freedom of Information Act request. The Galician Division and a Ukrainian nationalist organization he served in were both on a secret American government blacklist of organizations whose members were forbidden from entering the United States at the time.

Though records do not show that Karkoc had a direct hand in war crimes, statements from men in his unit and other documentation confirm the Ukrainian company he commanded massacred civilians, and suggest that Karkoc was at the scene of these atrocities as the company leader. Nazi SS files say he and his unit were also involved in the 1944 Warsaw Uprising, in which the Nazis brutally suppressed a Polish rebellion against German occupation.

Late Friday, Karkoc’s son, Andriy Karkos, read a statement accusing AP of defaming Karkoc, and pointed to the portion of the story about records not showing Karkoc had a direct hand in war crimes.

“That’s the god’s honest truth,” said Karkos, who uses a different spelling for his last name. “My father was never a Nazi.”

He said the family wouldn’t comment further until it has obtained its own documents and reviewed witnesses and sources.

Sam Rafowitz, an 88-year-old Jewish resident of the Minneapolis suburb of Minnetonka, grew up in Warsaw, Poland, and spent four years working in concentration camps. He took a hard line after hearing the news about Karkoc.

“I think they should put him on trial,” said Rafowitz, who was born near the border of Germany and Poland.

He may get his wish: Polish prosecutors announced Friday they will investigate Karkoc and provide “every possible assistance” to the U.S. Department of Justice, which has used lies in immigration papers to deport dozens of suspected Nazi war criminals. Karkoc lied to American immigration officials to get into the U.S., telling authorities in 1949 that he had performed no military service during the war. He became a naturalized U.S. citizen in 1959.

The AP evidence of Karkoc’s wartime activities has also prompted German authorities to express interest in exploring whether there is enough to prosecute. In Germany, Nazis with “command responsibility” can be charged with war crimes even if their direct involvement in atrocities cannot be proven.

Efraim Zuroff, the lead Nazi hunter at the Simon Wiesenthal Center in Jerusalem, said that based on his decades of experience pursuing Nazi war criminals, he expects that the evidence showing Karkoc lied to American officials and that his unit carried out atrocities is strong enough for deportation and war-crimes prosecution in Germany or Poland.

“In America this is a relatively easy case: If he was the commander of a unit that carried out atrocities, that’s a no-brainer,” Zuroff said. “Even in Germany ... if the guy was the commander of the unit, then even if they can’t show he personally pulled the trigger, he bears responsibility.”

Prosecution in Poland may also be a possibility because most of the unit’s alleged crimes were against Poles on Polish territory. But Karkoc would be unlikely to be tried in his native Ukraine, where such men are today largely seen as national heroes who fought for the country against the Soviet Union.

Karkoc now lives in a modest house in an area of Minneapolis that has a significant Ukrainian population. Even at his advanced age, he came to the door without help of a cane or a walker. He would not comment on his wartime service for Nazi Germany.

“I don’t think I can explain,” he said.

Karkoc and his family are longtime members of the St. Michael’s and St. George’s Ukrainian Orthodox Church, among several Catholic and Orthodox churches in the neighborhood.

“All the time I am here, I know him as a good man, a good citizen,” said the Rev. Evhen Kumka, the church’s pastor. “He’s well known in the congregation.”