It is happening all over again.

For half of his 72 years, Simon Wiesenthal has been stalking Nazi murderers around the world, an implacable avenger whose thirst for justice is never slaked. He has turned over the rocks that hid at least 1,100 of them, including Adolf Eichmann, and has hounded the infamous Angel of Death, Josef Mengele, now old and sick into a fearful half-life in Uruguay, where he dare not sleep more than a few nights in the same bed.

But a whole new generation of neo-Nazis is rising, especially in Europe, and the propaganda that keeps the movement alive is printed in America.

As usual, Wiesenthal gives names and addresses.

"The police raided 2,000 houses all over Germany one night this winter," he said, "and found stacks of neo-Nazi propaganda. It came from Lincoln, Nebraska."

According to Wiesenthal's newsletter, he gave American authorities the name of a man in Lincoln, Neb., as the American contact for German neo-Nazis. Propaganda also comes, he added, from Reade, W. Va., Mount Vernon, N.Y. and Arlington, Va.

"They are reprinting and selling all the Nazi books, big books, for $2 and $3. There is a lot of money behind this. Where is it coming from?

"It is not a powerful movement in America, but for Europe this is a disaster. It does concern the credibility of the United States, however, throughout the world. Because it allows the Soviet Union -- the big jail of nations -- to point to America as the source of this new poison and to set themselves up as the world's protector against Nazism."

Wiesenthal repeated his message last night before a sellout crowd at Lisner Auditorium during a quick visit here sponsored by the B'nai B'rith Hillel Foundation of George Washington University.

One does not interview Simon Wiesenthal. One does not need a list of questions. It's all you can do to get your pen out in time to record some small part of the passionate torrent. He is a man obsessed, and the possibility that the whole evil nightmare is starting again appalls him.

"One single day's propaganda mail can destroy a year of my work," he said.

"Half the population of the world today was not alive when the Nazi death camps were opened up in 1945. A tenth of the rest were children. That means 60 percent of the world's people know nothing at firsthand, nothing."

The anti-Semitic and fascist material is mailed to a post office box in Aarhus, Denmark, for distribution in Germany, he said. He has asked the Danes to stop the traffic, as he has the Americans and the Canadians, who have in Toronto a Samizdat Publishers Ltd., run by one Ernst Zundel.

"We have international cooperation on drugs, why not on this poison?"

Recently a Los Angeles synagogue was painted with swastikas and a message in German: "Jews -- the SS will come again." Bombings and other violence have been traced to fascist elements in Munich, Bologna, Paris.

"These groups may be small now," warned Wiesenthal. "They are not a mass movement but are organized in cadres. They are waiting for a crisis, economic or political. It's exactly what Hitler did."

He named six components that created the Holocaust: a dictatorship; hate as a government policy; technology; bureaucracy; a crisis of war; and a minority, any minority, to be singled out as victim.

"When we were young we used to laugh at the Nazis, they were so crazy," he said. "If it could happen in a country as highly developed and sophisticated as Germany, it can happen anywhere."

His famous documentation center in Vienna has a new branch now, dealing with neo-Nazism. He carries on with the old fight, too. Twenty thousand Nazi war criminals escaped in 1945, he believes, many of them aided unwittingly by American authorities who offered immigration to America as a reward for information. "There are a few hundred still in this country that we know of, but that's just the tip of the iceberg."

And Mengele -- the one he wants most of all, the man who injected blue dye into children's eyes to aryanize them, the man who collected twins for unspeakable experiments, the man who stood trim and handsome in his smart uniform beside the railroad tracks at Birkenau and pointed with his finger as the bedraggled thousands were herded past him: to the left, death; to the right, life. Wiesenthal has information that Mengele is planning a defense, should he be caught: The camp was supposed to kill them all, so in leting some live on as slaves, he was actually saving them.

"We should give him the Nobel Prize maybe," Wiesenthal smiled coldly.

He knows every move Mengele makes, in his precarious diplomatic shelter. He follows Mengele in his mind all the days, even when vacationing in Israel with his wife and daughter and three grandchildren.

"The man is 69 now," said Simon Wiesenthal. "I'm 72. We'll see. We'll see . . ."