The visit to Churchill's bunker had nothing to do with Evil Incarnate, and was not to be confused with Allan Ryan's trips for the Justice Department to Jerusalem, Berlin and Russia. It's just a story Ryan tells to illustrate the persistence of reality, the way in which history can hover in corners of the mind like an old scent which brings everything back.

"I've always been fascinated with World War II," he says. He heads the Justice Department's Office of Special Investigations, which has investigated 521 possible Nazi war criminals in the United States during the last three years. Since the crimes in question were committed before he was born -- he's 36 -- he's well served by this fascination.

"I was in England 10 years ago and this Britisher told me about a place that was open to tourists if they made a special request. It was the war rooms the British cabinet used, a bunker way underground. In 1944 they sealed it shut," he says, nursing a Heineken and a pipe through the gloom of an early evening in a downtown bar. He is telling this story in the tones of a man who wants you to know that it's the key to something.

"On the blackboard somebody had written, probably the same day they sealed it, 'Four Jerries downed.' You could walk into the room where Churchill slept. It was eerie, nothing had changed. There were still ashes in the ashtrays . . . "

The living history of death: Nothing has changed, but a world has vanished.

The subjects of Ryan's investigations have changed -- they have whole new lives. Most of them were from Poland, the Ukraine, Eastern Europe or the Baltic states (only two of his 22 cases now in court are Germans). In 1939, the vise began to tighten on them: Nazi Germany on one side and Communist Russia on the other. Millions of deaths later, they became displaced persons, as defined by Congress, and came to America. They settled into lower-middle-class neighborhoods and jobs, most of them, and spent 30 years living lives they would never have been able to imagine, here in the land of the Fresh Start, the New Life.

Only one thing didn't and couldn't change:

The prisoners were commanded off the bus, told to kneel on the edge of the anti-tank ditch . . . Then one of the officers . . . read the sentence and said that "You are condemned to die as a worthless race." -- Videotaped deposition by an Estonian witness

Ryan says: "I was told: 'The effort has to be made. You're not going to win any cases, but the effort has to be made.' "

He and his staff of 50 have 216 cases under investigation and 22 in court.

For example: Michael Dercacz, 71, of Astoria, N.Y., has been accused by Ryan's office in a denaturalization case of being a member of the Ukrainian Auxiliary Police "who systematically participated in the execution of Ukrainian Jews . . . The defendant personally assisted the German forces in the persecution of the civil population because of their race and religion . . . He guarded, beat and killed unarmed Jewish civilians."

According to the suit, Dercacz claimed to have been a Ukrainian farmer when he immigrated in 1949. His case is pending.

Ryan says: "What they say is, 'I wasn't there.' We show them, say, a Treblinka guard's ID card with their name on it, we show them a promotion record. They say, 'Okay, I was there, but I just patrolled the perimeter.' Then you say that witnesses saw them operating the gas chamber, and they say, 'Well, all right, I had to do it.' No one has said 'Let me unburden my conscience.' They are grudging, they will deny it, they will admit what they have to and then lie some more. They say there is a communist plot to get them, or it's the international Jewish conspiracy. We'll very often get this response from defense witnesses when we interview them before a trial. We ask when they first heard that the accused was in trouble, and they say: 'He called and said the Jews were after him.' They don't find it ironic. Maybe they don't think they did anything wrong. Maybe they thought they were home free."

Dear Mr. President,

What noble purpose is served by deporting a 73-year-old in poor health?

Dear Mr. President,

After 32 years of good citizenship can't this be forgiven? We are overrun with refugees now and allowing criminals to stay. -- Letters forwarded to the Office of Special Investigations

Ryan says: "As of two years ago, I'd say most cases came from letters to the Immigration and Naturalization Service, 'My neighbor is a Nazi,' that kind of thing. Now, we go out to lists and documents where war criminals are likely to be found. There's a place called the Berlin Documents Center, you can walk in and pull down a file, and there's the eagle, the swastika, just like it was."

He nods at the thought of the eagle and swastika. There were still ashes in the ashtray . . .

"We took a lot of those names from there and ran them against INS lists. We got a number of hits. We've done the same thing with the Poles -- they have good archives -- and to a limited extent with the East Germans. There are Jewish organizations in this country. We went to Israel, to Yad Vashem, the Israeli government document center of the Holocaust."

In Jerusalem, Ryan saw a picture that bothered him a lot, another one of those souvenirs of a lost world that it's his job to keep finding. "It was a photograph as big as that poster, and all it showed was a pile of children's shoes." He watches to see if the meaning of this has sunk in. He has green eyes and a short black beard masking enough of his face that his stare can get intense. "We are dealing with some of the most emotional and wrenching evidence you could ever have. We had a guy named Demjanjuk, he was the guy at Treblinka who ran the gas chambers. One witness who gave testimony against him was very soft-spoken, but you could hear every word of it in a very big courtroom. But you have to be professional. You can't just pick up a photo of piles of children's shoes, run to federal court and say: 'Take away this guy's citizenship.' "

Demjanjuk lost his case but filed a motion for retrial and also appealed the judgment against him.

Q: Can you tell us about the last time you saw that child?

A: He was dragging the girl out of the police station and she was crying out something in the Polish language . . . "Mother, he's going to shoot me. I want to live."

Q: What next?

A: I walked away. I was about 800 meters away from that spot when I heard shots. I'm a mother myself and it was for me quite a thing, I was feeling so sorry for her, that kid. -- Videotaped deposition

Ryan describes a hypothetical case: "Let's say we get a letter. It says, 'My neighbor is a Nazi -- Johann Schmidt, he was a guard at Treblinka. We go to INS, we get the file. If he was born in 1946, that's it, case closed. But say the file shows he was born in 1918, in a small town in the Ukraine. He was mobilized in the Red Army. He was captured six weeks later. He was a prisoner of war for four years. After the war he went to a displaced persons camp. This fits a common pattern of stories that aren't true. So we cable to the Berlin Documents Center. We cable to Poland -- they have good records on Treblinka. It turns out he went through Trawniki, which was a camp for training camp guards. If they send back his ID card from Trawniki, you've got a hot case, you're onto something.

"As it happens, in 1943, there was an uprising at Treblinka, and there are 200 survivors. We'd go to them. We'd show them a spread of eight visa photos, and one of them is Schmidt's. If we have two survivors out of five who say Number Four, we're in good shape. If we get material from the Berlin Documents Center, we're in good shape. If Schmidt was a member of the Ukrainian police, we'd send to the Soviet Union. Maybe six months later we get a cable back.

"The cable always says: 'At the time of the Great Fatherland War, in the Hitlerite Invasion -- they don't say World War II, they don't know what you're talking about."

The Soviets may provide more corroboration, or nothing at all. Ryan is aware that people suspect the Soviets will manufacture whatever suits their purposes, but he says they've played it straight, every time. Ryan's people comb through it all. They have maps to check testimony against. If the man says he was in a house by the railroad, they know where the railroad was. They have directories from towns occupied by the Nazis, they have police rosters, piles of paper which would have moldered into total meaninglessness were it not for the persistence of memory which led then-congressmen Joshua Eilberg and Elizabeth Holtzman to demand in 1978 that our government search for these people, almost 40 years after their crimes were committed. Out of their efforts, Ryan's office was established.

Ryan needs to prove only that a war criminal lied on his entry forms when he came here. That's technically sufficient to win in court and get a deportation order. But in fact, he has to prove atrocities, rescue them from history . . . the pile of children's shoes . . . So they send teams of lawyers and videotape operators to Eastern Europe, with the cooperation of the Soviet Union.

It is a big, high-ceilinged room in Estonia with brown wallpaper and molding that implies some halfhearted nostalgia for one glorious past or another. At a long table sit two Justice Department lawyers, a Soviet translator in tinted glasses, and Elmar Puusepp, who is 74. He is the witness. The rest of them are taking his deposition in the case of Karl Linnas, who is accused of commanding the guards at a concentration camp at Tartu, Estonia.

Puusepp has white hair, and he is very nervous. He looks like his wife probably stuffed the handkerchief into his jacket pocket while he was kissing her goodbye. He was on the Russian side, the political officer in a tractor factory when the Nazis arrived, and organized the Omakaitse, a local police organization of which he says one Karl Linnas was a member.

"He says to me, 'Ukrainian, you live enough. Now you are going with me,' " Puusepp says through the translator, who speaks in a British-tinged accent full of hesitations that reduce the testimony to the gray detritus of bureaucracy.

Q: Did you know where the train was going?

A: Oh yes, to Belzec.

Q: And what was at Belzec?

A: Crematorium.

Linnas' case is pending.

There are stacks and stacks of videotapes. They show a man talking about Nazi troops crashing into his home with dogs. "He was 16 when it happened, he kept saying, 'My own home!' " Ryan says. "Or a woman who escaped from a death train, not because she expected to survive, but to give hope and inspiration to the people trapped inside. Or a man who cries instantly on being asked if he's married. His wife was killed during the war, but not before a guard took the opportunity to use his rifle butt to crush the head of the baby she held in her arms.

Dear Mr. President:

It appears to be the height of hypocrisy to collaborate with the Soviet Union . . . the Zionists become hysterical . . . Who persecuted the bombing of Hamburg or Dresden? . . . Led by Russian Jews, its tentacles begin to be spread all over the world . . . Simon Weisenthal I can understand, he is a Jew, he lived through the terrible times . . . -- Letters forwarded to the Office of Special Investigations

Says Ryan: "The man who put me in this office went home to his wife and said, 'Ryan's got a good point and a bad point. The bad point is that he's not Jewish. The good point is that he's not Jewish.' "

The walls of Ryan's offices are hung with maps of Polish and Ukrainian towns; with travel posters from Israel; with lots of World War II posters that bring it all back, Ryan being a man with a capacity for the flesh and blood of history:

FINISH THE JOB -- SUBSCRIBE TO THE VICTORY LIBERTY LOAN.

UNITED WE ARE STRONG; UNITED WE WILL WIN.

And the books in his shelves: "While Six Million Died" and "The Holocaust Years" and "Never to Forget."

Because all Jews, no matter where they were captured, from a cellar or where, they were all executed or shot . . . I heard screaming in the barracks and I saw that the guards had pressed a prisoner's head between his legs at the back, the prisoner's back, and was beating the back of that prisoner with a German army belt, leather belt . . . And the 20 on the left hand side were taken -- were meant for the death barracks and other 20 were meant to be working . . . -- Videotaped depositions

Ryan says: "This was not a Lt. Calley situation. This was not combat. We're dealing with people who weren't on the front lines."

He says: "Last year I went to Dachau. The tour took three or four hours. I walked carefully through the museum. I saw the old newspapers, the artifacts, the mess kits and uniforms. I got out to the end and walked into the sunlight and saw all the buildings, the barracks and the crematorium. And I said, 'How could this have happened?' You say to yourself, 'I cannot believe that it could have happened.' Somebody shoots a drug dealer on 14th Street -- that you can understand, but this, no. So can I put myself in their shoes? No."

Crematorium . . . my own house . . . Ryan has a wife and a baby daughter. He is fond of Irish folk music. He once clerked for Supreme Court Justice Byron White. He once was an officer in the Marines. He has written but not yet published a novel about lawyers in Washington. He does not plan to write a novel about Nazis. Maybe it's too real. After an article about Ryan appeared, his family got a number of telephone threats.

Then again, it can never be real. He tries hard, but he'll never understand.

"Feodor Fedorenko was a guy who was typical. Before the war he was a Ukrainian farmer. In July of 1941, the Russian army said, 'You and your truck are drafted.' Two weeks later he was captured. The Germans came in looking for camp guards. He went to the training camp at Trawniki -- he said it was involuntary, but I don't believe it. (And U.S. law does not differentiate between voluntary and involuntary war crimes.) He was the equivalent of a corporal. We had six survivors of Treblinka who saw him shoot people, beat people, and whip people as they got off the train, with a leather whip with steel bars at the end of the whip. One witness said he told a prisoner to get down on all fours, then put a pistol in his ear and blew his head off.

"I sat in the courtroom and looked and looked at him, trying to understand. You could never believe he or anybody else could have done that, no way."

The government won its denaturalization case against Fedorenko, but deportation proceedings remain.

It's strange that the survivors, the very people who can and have to believe it, have no desire for revenge when they talk to Ryan.

"They say: 'All we want is for justice to be done.' They say: 'How can there be revenge for 6 million people?' They really believe that, and they saw their families killed. It's people who never saw any of it, like the Jewish Defense League types, who would want to throw a bomb at these peoples' houses."

Never forget.

Ryan has gotten six rulings in favor of the government. He has reinvestigated and dropped the much-publicized case against Frank Walus of Chicago for lack of evidence. Despite deportation orders, appeals have kept all convicted defendants in the country. One has died. Pretty soon they'll all be dead, or too feeble to conduct their defenses, and Ryan will move on to some other job, having fought a war which consisted of stacks of videotapes, piles of legal briefs . . . ashes in the ashtray, a pile of shoes; Soviet witness looking at the videotape camera and sucking his teeth in fear; eagles and swastikas . . . and his final inability to really know beyond belief that any of it ever happened at all.