Jakob Reimer could almost be a poster child for the American dream.

He settled in the Bay Ridge section of Brooklyn in 1952. After starting out as a bartender in the Times Square Schrafft’s, he worked his way up to manager and part-owner. He ran the Wise Potato Chips franchise in Brooklyn, was married, had two kids, got divorced, then remarried. He never even got a parking ticket. The image would be perfect if it weren’t for his past as a Nazi officer who helped clear Warsaw and other cities of their Jews. Jakob Reimer had actually saved the photo from his Nazi ID card.

So perhaps it’s not surprising that he didn’t show up the other day for a court date that could lead to his deportation.

His lawyer, Ramsey Clark, the former attorney general, told the court that a couple of days earlier, he had called his client to get ready for their court date. Mr. Reimer’s phone had been disconnected. Concerned, Mr. Clark sent a staff member to Mr. Reimer’s apartment, where, it turned out, the mail was piling up and there were indications that Federal Express had twice tried unsuccessfully to deliver a package.

That package contained the Justice Department’s brief arguing Mr. Reimer should be deported.

Mr. Reimer, who is 86, was stripped of his citizenship two years ago for failing to disclose on his visa application his time as a concentration camp guard and his involvement in the removal of Jews from their ghettos. He is one of more than 100 suspected war criminals living in America who are being investigated for allegedly having lied about what they did during World War II.

“They came here, covering up their past, and hoped people would forget and move on,” the director of the Justice Department’s Office of Special Investigations, Eli Rosenbaum, said. That office tracks war criminals.

The pursuit of Mr. Reimer has gone on for more than 25 years. He was first interviewed in February 1980. His name had surfaced on a list of people who had been guards at the infamous Trawniki camp. At the time, the Department of Justice lawyers weren’t particularly interested in him. They were after a bigger target, John Demjanjuk, who they thought was an infamous guard known as Ivan the Terrible, and they hoped Mr. Reimer could help build their case.

They didn’t know a lot about Mr. Reimer at the time. His application for a visa said he was a Ukrainian who was drafted by the Soviets in 1940 and, soon after, captured by the Germans, who put him in a prisoner-of-war camp. Once released, he wrote in his application, he was forced to work for the German army, first as a guard at Trawniki, then as a trainer of guards, and finally as an interpreter and a paymaster.

The interview did not go well.

The federal lawyers reported that Mr. Reimer “made a pathetic impression,” he was worse than evasive, he had been vague, and he seemed truly unaware of what they were asking him about. They concluded that he had “no useful information” and, despite proof he had been at Trawniki, that prosecuting him would be a waste of time for everyone involved.

The Office of Special Investigations moved on, continuing to focus on Demjanjuk and finding other high-priority cases. Mr. Reimer faded into the background.

Until 1989. The Soviet Union, which was beginning to open up, had started to cooperate with American efforts to track war criminals. As part of those efforts, they turned over eight pages of documents relating to Mr. Reimer. Apparently, Mr. Reimer had omitted some material from his visa application.

Not only had he been a guard at Trawniki, but while there, he became a member of the Wachmannschaften, the division that specialized in emptying ghettos of their Jews and escorting them to concentration camps. The documents from the Soviets showed that Mr. Reimer had been at the Czestochowa and Warsaw ghettos when they were cleared, their residents sent to the camps.

The investigation into Mr. Reimer was reopened.

From the Soviets, the Office of Special Investigations also received transcripts of interviews conducted by the KGB in 1964 with two Soviets who had been taken prisoner by the Nazis and forced to work at Trawniki. Both said they knew Mr. Reimer. One of them, Nikolaj Leontev, said he was in a unit commanded by Mr. Reimer to empty a town in Czechoslovakia of its Jews and execute them in a forest.

“During the march, the Jewish prisoners began to throw their things away and were very upset,” Leontev told the KGB. “The children and women were crying. … Deep in the forest … we saw a large pit had been dug out … all of the doomed people had to sit down about 10 meters from the pit. … Mr. Reimer and others … used their rifle butts to prod the victims and force the fear-crazed people to stand up in groups. … They then marched them to the pit and then, along with the Germans, shot those people.”

In May 1992, a month before Mr. Reimer would be charged, he was invited to meet with the Department of Justice’s Mr. Rosenbaum and one of his colleagues. In the interview, he allegedly admitted having participated in war crimes but maintained he’s now an American and the past is past.

“I did not volunteer for this Trawniki business,” Mr. Reimer said. “I was ashamed of it. I didn’t want to remember it. I have been a model citizen in this country, not even a traffic ticket. It would be the worst punishment for me to be deported from this country. This is the only country I know.”

While he tried to run from his past, no one was buying. A judge stripped him of his citizenship.

Now the question remains, is Mr. Reimer on the run again, or will he make it to court to face likely deportation?

Mr. Clark wouldn’t say where Jakob Reimer is or how come he missed court but maintained he hasn’t fled.

“He’ll be in court on June 17th,” when the hearing’s been rescheduled, Mr. Clark said.