MINNEAPOLIS — Authorities in Poland moved quickly to issue an arrest warrant for a Minnesota man accused of participating in a World War II massacre, just two days after determining they had enough evidence to charge him.

But many steps remain before 98-year-old Michael Karkoc would ever face charges overseas. His family has said he has dementia, but legal experts say health problems aren’t a defense against extradition under U.S. law.

Here’s a look at what’s next in the case:

The background

Karkoc is accused of commanding a unit in the Nazi SS-led Ukrainian Self Defense Legion that raided the eastern Poland village of Chlaniow in July 1944, killing 44 people, including women and children.

Polish prosecutors’ decision to seek his extradition came four years after The Associated Press published a story establishing that he commanded the unit, based on wartime documents, testimony from other members of the unit and his own Ukrainian-language memoir. The story also established he lied to American immigration officials to get into the U.S. a few years after the war. A second report uncovered evidence that Karkoc himself ordered his men to attack the village.

His family has consistently said he was innocent of any war crimes, challenging the validity of the evidence against him and depicting him as a Ukrainian freedom fighter who fought against the Germans.

How extraditions work

Polish prosecutors are expected to ask their foreign ministry to forward their extradition request to the U.S. State Department, which would relay it to the federal prosecutor’s office in Minneapolis to begin court proceedings. Karkoc would then be brought before a federal magistrate judge, where he could seek bail. The magistrate would set a date for a hearing when he could present any defenses he might have against extradition.

But according to legal experts, his defenses are few.

“In order to secure extradition, the government of Poland is going to have to provide probable cause that this individual committed the crimes charged. That will be the battleground in an extradition case,” said Jacques Semmelman, a New York attorney and former federal prosecutor who specializes in extradition law.

Age and health are not defenses against extradition under U.S. law, and Karkoc does not appear to have any other defenses, Semmelman said.

“I have every expectation that this man is going to be found extraditable,” he said.

Before that happens, Karkoc’s attorneys could argue that his health counts as a special circumstance that provides grounds for bail, said Karen Snell, a San Francisco attorney who works in extradition defense. But it’s much harder to get bail in an extradition proceeding than a criminal case, she said.

Karkoc could appeal if the magistrate rules he should be sent to Poland. Semmelman said he knows of cases where that process has taken up to two years.

His health

Karkoc is 98. His son, Andriy Karkoc, refused to disclose details about his father’s health to the AP except to say he’s not competent. He told the Minneapolis Star Tribune on Monday that his father lives in an assisted-living facility while his mother is in an attached memory care unit. The family has previously said he has Alzheimer’s disease.

German prosecutors shelved their own war crimes investigation of Karkoc in 2015 after concluding that he was not fit for trial.

Karkoc’s attorney refused to allow a medical expert from Germany to assess his ability to be questioned and stand trial, according to Munich prosecutors, but instead provided documentation from his American doctors. Munich prosecutors called the assessment “comprehensive.”

Germany’s decision

The German probe began after AP’s story in 2013. The evidence was assessed by Germany’s special federal prosecutors’ unit that investigates Nazi-era crimes, which concluded there was enough for Munich state prosecutors to pursue murder charges against Karkoc.

In 2014, the Federal Court of Justice said Karkoc’s service in the SS-led unit made him the “holder of a German office.” That gave Germany the legal right to prosecute him even though he is not German, his alleged crimes were against non-Germans and they were not committed on German soil. Someone in that role “served the purposes of the Nazi state’s world view,” the court said.

Other war crimes cases

One of the highest-profile cases involved retired Ohio autoworker John Demjanjuk. He died in a German nursing home in 2012 at age 91 while appealing his conviction there for being an accessory to 28,060 murders while a guard at the Sobibor death camp.

The Ukrainian-born Demjanjuk spent most of his 18-month trial in Munich lying in a special bed brought into the courtroom.

Demjanjuk fought for 35 years to clear his name after he was first accused of being a notoriously brutal guard at the Treblinka extermination camp known as “Ivan the Terrible.” He was extradited from the U.S. to Israel in the 1980s, tried, convicted, and sentenced to death. But the Israeli Supreme Court overturned the verdict and returned him to the U.S. in 1993 after it received evidence that another Ukrainian was that guard.

The U.S. deported him to Germany in 2009.