There’s a long road ahead in determining whether allegations that 94-year-old Michael Karkoc of Minneapolis once led a Nazi military unit will force him to leave the United States.

German and Polish authorities have expressed interest in pursuing war crimes investigations against the Ukrainian immigrant, but authorities will first need to prove that Karkoc lied on his U.S. citizenship application when he said he hadn’t fought in World War II.

The United States would have to revoke his citizenship — a rare step — before he could be deported to face another country’s war crimes charges.

But St. Paul immigration lawyer Kim Hunter suggested Karkoc’s case will be closely examined.

“These are very high priority cases for the U.S. government,” Hunter said.

Karkoc, a retired carpenter living in northeast Minneapolis, has received worldwide attention since the Associated Press reported Friday that he had served as an officer in a Nazi SS-led military unit responsible for burning villages and killing many civilians in the final years of the war. Although the AP reported it had not found evidence that Karkoc took a direct hand in war crimes, it said he had apparently been present during several atrocities, including the vicious suppression of Polish nationalists by the Germans in the 1944 Warsaw uprising.

On Saturday, Karkoc’s family continued to deny the allegations through an attorney. Karkoc’s son called the AP report “sensationalist and scandalous” at a Friday news conference.

AP Media Relations Director Paul Colford said Saturday in a statement that the organization stands by its story.

“It’s been thoroughly reported,” he said, “including a description of Mr. Karkoc’s own memoir documenting his past.”

Several other national and international cases involving alleged Nazis have shown that time can be the enemy when events are so far removed, the accused are so elderly and so few witnesses remain.

In 1990, an 81-year-old Minneapolis man died in a nursing home before the Justice Department could strip the Latvian immigrant of his citizenship and deport him for war crimes. In 2011, John Demjanjuk was convicted of his role in the killing of 28,000 Jews at a Nazi death camp in Poland, but he died while an appeal was pending.

Still, local and national Jewish human rights groups are pressing federal investigators to take action.

“We should take our historical responsibility seriously,” said Steve Hunegs, executive director of the Jewish Community Relations Council of Minnesota and the Dakotas.

“If it’s true, he’s been hiding here all these years,” he said. “Suddenly the eyes of the world will be on us.”

Age may prevent trial

According to the AP, Karkoc told immigration officials in 1949 that he had performed no military service during the war; he became a naturalized U.S. citizen in 1959. Proving he lied on his citizenship form, an offense that would allow Karkoc to be stripped of his U.S. citizenship, could take six months to a year, experts said.

Even then, said University of Minnesota Law School Prof. Fred Morrison, Karkoc may not automatically be deported from the United States.

Another option, Morrison said, is for Karkoc to be extradited to Poland or Germany, which could happen even if Karkoc maintains his U.S. citizenship.

Still, Karkoc’s age means he may never live to see a trial.

“Because of his age, it seems he’d realistically not be tried for his war crimes,” Hunter said about the 94-year-old. “It is a sort of race against time.”

In a letter to a director at the Justice Department, the Simon Wiesenthal Center, an international Jewish human rights organization in California, urged authorities to immediately open an investigation of Karkoc. His age “should have no bearing on the fact that he has never answered for the crimes he is suspected of committing,” the letter argues.

Hunegs pointed out that there is no statute of limitations on lying to immigration officials or for murder. While it’s a long process, authorities should still pursue the case against Karkoc, he said.

The decades that Karkoc has lived in Minnesota, Hunegs added, are a “brazen” affront to Holocaust survivors and World War II U.S. veterans.

“To think that the very people that [veterans] fought may have received refuge in this country is unfortunate,” he said.

Just last month, a former Chicago resident and suspected Auschwitz concentration camp guard, Hans Lipschis, was arrested in Germany — he was No. 4 on the Wiesenthal Center’s list of most wanted Nazi criminals. The 93-year-old was deported from the United States in 1983 after the Justice Department accused him of concealing his Nazi past when he immigrated to the United States about 1956.

In Minnesota, Edgars Inde, a Latvian immigrant accused of committing Nazi war crimes, died before the U.S. government could finish a case against him.

In 1988, Inde was linked to a secret Latvian police unit that executed thousands of Jews during the German occupation. He was the first Minnesotan that the U.S. Office of Special Investigations sought to deport for alleged involvement in Nazi atrocities.

U.S. investigators argued that he concealed his identity and lied about his membership with the police unit. Inde denied the allegations and the case stalled when his health failed. It was dismissed at his death in 1990.

No matter its conclusion, Karkoc’s case is likely to make history because of the way it surfaced, with a British amateur historian contacting the AP after doing an online search on Karkoc.

Morrison, the U professor, said it could spur new cases.

“That makes a big change in the ways things can be pursued,” he said. “Really you can’t hide in plain sight anymore.”