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WARSAW, Poland — Poland will seek the arrest and extradition of a Minnesota man exposed by The Associated Press as a former commander in an SS-led unit that burned Polish villages and killed civilians in World War II, prosecutors said Monday.

Prosecutor Robert Janicki said evidence gathered over years of investigation into U.S. citizen Michael K. confirmed "100 percent" that he was a commander of a unit in the SS-led Ukrainian Self Defense Legion.

He did not release the last name, in line with Poland's privacy laws, but the AP has identified the man as 98-year-old Michael Karkoc, from Minneapolis.

Michael Karkoc works in his yard in Minneapolis in 2014. Richard Sennott / AP

"All the pieces of evidence interwoven together allow us to say the person who lives in the U.S. is Michael K., who commanded the Ukrainian Self Defense Legion which carried out the pacification of Polish villages in the Lublin region," Janicki said.

The decision in Poland comes four years after the AP published a story establishing that Michael Karkoc commanded the unit, based on wartime documents, testimony from other members of the unit and Karkoc's own Ukrainian-language memoir.

Karkoc's family has repeatedly denied he was involved in any war crimes and his son questioned the validity of the evidence against him after Poland's announcement, calling the accusations "scandalous and baseless slanders."

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"There's nothing in the historical record that indicates my father had any role whatsoever in any type of war crime activity," said Andriy Karkoc.

He questioned the Polish investigation, saying "my father's identity has never been in question nor has it ever been hidden."

In Poland, prosecutor Andrzej Pozorski said Karkoc would be given a full opportunity to tell his story.

"This person has not been questioned in the capacity of a suspect so it is hard to react to his explanations, because we don't know them," said Pozorski who heads the investigative team at a state institute.

Prosecutors with the National Remembrance Institute, which investigates Nazi and Communist-era crimes against Poles, have asked a court in Lublin to issue an arrest warrant for Karkoc. If granted, Poland would seek his extradition, as Poland does not allow trial in absentia, Janicki said.

He added the man's age was no obstacle in seeking to bring him before justice.

"He is our suspect as of today," Janicki said.

If convicted of ordering the killing of civilians in 1944, Karkoc could face life in prison.

The U.S. attorney's office in Minnesota declined to comment on the case.

Prosecutors in Germany shelved their own investigation of Karkoc in 2015 after saying they had received "comprehensive medical documentation" from doctors at the geriatric hospital in the U.S. where he was being treated that led them to conclude he was not fit for trial.

The investigations in Germany and Poland began after AP's story in June 2013, which established Karkoc was a commander of the unit and then lied to American immigration officials to get into the United States a few years after the war.

A second report uncovered evidence that Karkoc himself ordered his men in 1944 to attack a Polish village in which dozens of civilians were killed, contradicting statements from his family that he was never at the scene.

"The Associated Press stands by its stories, which were well-documented and thoroughly reported," said Lauren Easton, director of AP's media relations, on Monday.