Is Raoul Wallenberg alive?

On Jan. 17, 1945, the Swedish amateur diplomat, who had been credited with saving the lives of at least 20,000 Jews in Hungary during the last mad months of Nazi rule, appeared at the Jewish relief office in Budapest. He said he was being taken to see Marshal Rodion Malinovsky, leader of the conquering Russians.

"I'm going," he said. "I don't know if it's as their guest or their prisoner."

Soviet soldiers were waiting downstairs to accompany him to the marshal's headquarters 140 miles east.

Wallenberg was never seen again - outside Russia.

Over the years, the Swedes sent notes demanding word of him. The Soviets denied word of him. The Soviets denied any knowledge of the case. Finally in 1957 the Russians admitted that they had found records indicating the man had died 10 years earlier in a Moscow prison of a heart attack. He would have been 33 at the time.

The trouble is, a steady parade of people released later from Soviet gulags has reported meeting Raoul Wallenberg. Until 1953 he was supposed to have been in Verchneuralsk prison camp. Two years later, in Irkutsk. In the late '60s, in Cell 23 of Corpus II prison. As late as 1975, in the hospital of Butyrka prison in Moscow.

Three years ago a Russian Jew, Jan Kaplan, was released from prison and phoned his daughter in Israel. To reassure her of his condition, he told her he'd met in Butyrka hospital a Swede who had been in prisons for 30 years "and didn't look bad at all." Kaplan was rearrested.

"We've had word as late as this February," said Nina Lagergran, Wallenberg's stepsister, who has come to Washington seeking support in her long fight to free the phantom prisoner. With her is Annette Lantos, one of the thousands of Jews whose lives Wallenberg saved.

Mainly, they want to reactivate a stiff State Department memo to the Russians, written in 1973 but blocked at the time by Henry Kissinger without comment. They also hope to see Secretary of State Cyrus Vance and confer with Sens; Frank Church and Claiborne Pell who have already asked President Carter to intervene. They will also approach the U.N.

"It would be wonderful if we could have my brother nominated for the Novel peace price," Nina Lagergren said quietly. "That would do something, I think."

The idea is not so fantastic. It has nothing to do with the fact that the Wallenbergs are something like the Rockefellers of Sweden, a banking family that controls SAS airline and other large enterprises. The man had his own achievements.

By mid-1944 half a million Hungarian Jews had been deported in a last-gasp Nazi paroxysm of hate. There were still 200,000 left, and Sweden, with undercover American backing, picked the aristocratic young man - descendant of statesmen and financiers, an architecture graduate of the University of Michigan, an idealist who had most recently been working in a Palestine bank - to attempt the rescue.

Rushed to Budapest with accreditation as third secretary of the Swedish legation, Wallenberg worked with the reckless fervor of the possessed.

He designed and printed a special Swedish passport and handed out 5,000 of them to Jews. With his own money plus about $50,000 supplied by the Americans, he leased 32 apartment buildings, flew a Swedish flag over them and sheltered another 13,000 people, sometimes actually guarding the entrances himself against the fanatic Arrow Cross, anti-semitic Hungarian fascists, and the S, all of whom were trying to exterminate as many Jews as they could before the Russians overran Hungary.

Other neutral nations in Budapest, followed Wallenberg's example, the Swiss, the Portuguese, saving another 20,000.

And when the Russians arrived at the gates of Budapest, Wallenberg wanted to talk to their leader about returning the property of the victims. He was warned not to go. Perhaps he could not believe that the Soviets would hate Jews too, or that they might suspect him of being some sort of spy.

Though it was only in 1977 that a word from the famed pursuer of Nazi criminals, Simon Weisenthal, first brought the case international publicity, for some people it is an old story. His mother and stepfather, Maj and Fredrik von Dardel, worked for 34 years to find him, to get word. Early this year, just after the latest discouraging note from Moscow, they died, aged 87 and 93, within two days of each other.

There are others. All over the world, thousands and thousands of Jews who are alive because of Raoul Wallenberg want a chance to do something for him.

"That is why I am in Washington," said Annette Lantos. She and her husband, Dr. Thomas Lantos, were personally retrieved from the Nazis by Wallenberg and stayed on to help him.

A group, Concerned Citizens for Wallenberg, writes letters to him in Moscow in hopes of embarrassing the Russians, who still deny his existence though the name and the story are well known to the average Muscovite.

Already the British have expressed concern, and in Israel, Prime Minister Begin has cabled Carter asking him to query the Soviets.

"They know," said Nina Lagergren, her blue eyes flaring. "They know where he is." CAPTION: Picture 1, Nina Lagergren, by Joel Richardson; Picture 2, Raoul Wallenberg at age 23