In 1942 a German industrialist risked his life by revealing the secret of Hitler's order to exterminate European Jewry.

Only one person is still alive who knows this man's identity. He is Gerhart Riegner, in Washington last week for a meeting of the World Jewish Congress, the most influential international Jewish organization. He is now a portly, pink-cheeked gentleman of 71. Dressed in a three-piece suit, of a heavy woolen cloth of midnight blue, he looks like the mayor of a Swiss town: stolid, somber and exceedingly respectable.

During the war, Riegner was--and is still--the representative in neutral Geneva of the World Jewish Congress. Then he was a brilliant young legal counsel; now his title is secretary general. Then he was a refugee from Germany, one of the few the Swiss agreed to admit. He still travels with the laissez-passer of a stateless refugee; after close to 50 years of residence, he hasn't been able to bring himself to apply for Swiss citizenship and passport.

"It took two days to persuade myself that the industrialist was telling the truth," Riegner now says, "and finally I came to the conclusion that it was possible and probable." Riegner then went to the American and British diplomatic representatives and asked them to transmit the information to their governments and to key Jewish leaders.

That now-famous telegram--sent Aug. 8, 1942--and others that followed were curtly dismissed in the State Department and Whitehall as "the opinion of one Jew in Geneva."

The State Department advised the U.S. legation in Switzerland that Riegner's charges were "unsubstantiated" and waited for 20 days to send a copy to Rabbi Stephen Wise, the key American Jewish leader of the time, to whom Riegner had originally addressed his cable. Undersecretary of State "Sumner Welles told Wise not to publish it," Riegner says. "In wartime it was an order."

For several months, no Allied or neutral official believed the industrialist, who heard about the plan during his many visits to Hitler's headquarters. He had free access to top Nazis because his factories, with their 30,000 skilled workers, were pressed into the service of the German war machine. The industrialist's fervent hope was that once the world learned of the death camps, it would do something to stop them.

"Nobody really believed it," Riegner says. "Not even Jews who knew it. For instance, at the height of the extermination policy I counted 4 million Jews as dead. My own office in New York--where I sent all my reports and which was directed by a great Jewish leader--published the figure of only 1.5 million."

The recent controversy over the Holocaust Inquiry Commission led by former Supreme Court justice Arthur J. Goldberg deals in large part with what American Jewish organizations did or did not do in response to Riegner's cable. Riegner says he welcomes an impartial inquiry by independent scholars. But, he charges, the commission as it is now constituted is "ideologically fueled by people determined to rewrite history." The people Riegner criticizes are associates of Israeli Prime Minister Menachem Begin, "who want to indict the Zionist establishment" of neglecting rescue work.

Riegner tells how another American Jewish leader sent him a list of 30,000 addresses of Jews in Poland and asked the Geneva office to send food packages to those addresses. "That was in 1943 or '44," Riegner says. "What madness! They saw all my reports and knew that none of those addresses were valid. Those people were . . ."

Riegner doesn't complete the sentence. He stares into space, purses his lips and declares slowly, flatly, impassively: "They knew it but they didn't believe it."

Riegner, however, was convinced. At 30, he was "an unexcitable, serious young man," he recalls, "always a well-balanced type." Having studied law in Germany and then in France, he intended to become a professor of jurisprudence. He saw himself as following in the footsteps of his father, once Germany's minister of justice, and a person drawn to the philosophy of law. "I come from a typically German-Jewish bourgeois family very deeply embedded in German culture, a humanistic tradition, interested in philosophy, history, art," Riegner says. "But also roots in Jewishness."

From the time Riegner saw Nazis beating up Jews and other political enemies on the streets and in the universities, he was a stiff pessimist in face of what he calls "the Jewish optimism of the centuries--a kind of wishful thinking, really."

Unlike many other Jews, who dismissed Nazism as an episode and predicted that Hitler would soon run out of steam, Riegner argued that Jews should leave Germany while they still could--he left in May 1933, four months after Hitler became chancellor. He read "Mein Kampf" and listened to Nazi slogans and songs. "From my first encounter with Nazi terror, I took the Nazis seriously," he says. "Hitler made many speeches in which he threatened to destroy the totality of Jews.

"Why people didn't believe is a question I have always struggled with. It was so terrible that the human mind refused to accept it. An encounter with absolute evil is something very few people are prepared to accept. It is a paradox: The most positive experience is that people can't accept evil. That means that man is basically good."

At the time Riegner had no doubt: The industrialist was telling the truth, and all other evidence supported the report.

Headquartered in Geneva, only a few miles from Germany and France, Riegner collected information, all of which confirmed the industrialist's report. The list of witnesses grew every week. A Jew who survived two massacres (36,000 dead) in the ghetto of Riga and reached Switzerland; a Swiss employe in the consulate in Prague briefed by Czech Jews on deportations; a Polish Jew who was smuggled out of Russia by a disaffected German officer warning him about the extermination camps he had seen; messages, smuggled out by French railway workers, of mass roundups of West European Jews for transportation to concentration camps in the east.

There was even testimony from a Danish Jew close to Field Marshal Hermann Goering--"Goering had such strange associations," Riegner explains, "and we asked ourselves how reliable he was"--who somehow smuggled to Geneva a sheaf of the railroad schedules for Jewish transports. In a supreme example of bureaucratic punctiliousness, the German railways billed the Berlin Jewish community for the cost of the deportations.

Riegner kept filing the reports, kept asking for action. "We never did enough," he says. "Sure, we could have done more. All of us. In 1944 Wise finally got the American government to agree to a free port admitting 1,000 Yugoslav Jews. It was a procedure to postpone immigration problems. It could have been done with thousands of others. Also, we could have put stronger pressures on the neutrals--Sweden, Turkey--to accept more refugees. We could have brought more people to England, to North Africa.

"Hitler could have been stopped several times, but once he started rolling, only thousands, maybe tens of thousands of Jews could have been saved. Not millions."

The industrialist, ostensibly in Geneva on business, met Riegner three times, each time warning of the rising number of Jews being killed. He passed on details such as the kind of chemicals used in the gas chambers.

The industrialist was frustrated that nothing was happening, Riegner says. "In December 1942, finally, there was a condemnation of the massacres of Jews from London, Washington and Moscow. The British Parliament rose in two minutes of silence. But they wouldn't act."

Riegner says he does not know why the industrialist wanted to remain unknown. Fear of revenge against his family might have been a reason, Riegner says. He adds that it is possible that the industrialist never told his family about his role. "I wrote to his wife after his death," Riegner says, "and I alluded to his service. I think his wife might have known. Perhaps. But not his children. I don't know. For me, what mattered was that he was a democrat, deeply anti-Nazi--a man of great moral standards who wanted to relieve his conscience."

On one occasion, Riegner concedes, he was forced to reveal the industrialist's name. When he made "a desperate attempt" in the fall of 1942 to convince the Americans of the truth of the death camps, Riegner wrote down the industrialist's name, put it in a sealed envelope and handed it over to the head of the American legation in Bern. This was a few days after the industrialist had warned Riegner that he now had definite information on Hitler's direct order to exterminate all Jews. Riegner put all the evidence together in a document of 25 pages, to be transmitted to Washington.

But the envelope has disappeared, Riegner says, and an inkling of a sly grin spreads across his impassive face. The sealed envelope is not in the American archives, Riegner says, the U.S. diplomat is dead and no researcher has come up with the industrialist's name.

"I gave my word not to give out his name," Riegner now says. "I am bound to my word. He never asked for anything else. Many people have approached me to give out his name, but I did not break my word. I never will."