A West Coast Anti-Defamation League official said yesterday that his organization is investigating a hoax letter written on bogus United Nations stationery asking talent agents for names, addresses, telephone numbers and biographies of "those entertainers who support the Zionist, racist state of 'Israel.' "

David Lehrer, the Los Angeles-based western states counsel for the Anti-Defamation League (ADL) of B'nai B'rith, said, "We're trying to see if we can isolate the source . . . We're trying to see who would have purchased a list of talent agents. We have referred the matter to the New York Police Department and the chief of security at the United Nations."

Lehrer did not speculate on who he thought was responsible: "Somebody who thought they were making a joke. But it's not funny."

The Association of Talent Agents, a trade organization, began receiving reports of the letter from its members last Wednesday and Thursday, according to executive director Chet Migden. "Everyone was very angry about it," he said.

Migden said he had no idea how many of his association's 170 members had received the letter. "I would say in the first couple of days we were inundated with calls," Migden said. "I didn't log them, but I'd say it was 20 or 25 . . . It was debunked so rapidly. Most people heard that it was a phony, and complaints stopped pretty quickly."

Lehrer said most of the reports of the letter came from Los Angeles, but "we know it was received in some other cities," Lehrer said. "Minneapolis, for instance."

According to Migden, who has a copy of the letter, it comes from a nonexistent "United Nations Extraordinary Commission on Zionism and Racism" and is signed by "George Assayid, director." U.N. spokesman Francois Giuliani said, "There is no such person in the U.N. phone book of staff members" and that "there is no commission on Zionism and racism -- obviously, it's a hoax letter."

United Nations security chief Augustin Vaz said yesterday that he had just received information from the ADL about the letter, "so we are going to look into it."

According to Migden, who read from his copy, the letter says that "following the great success of the U.N. Special Committee against Apartheid's register of performers it has been decided to extend the register to those entertainers who support the Zionist, racist state of 'Israel.' "

The letter, mailed from New York, says, "Please help the United Nations to bring about a similar cultural isolation of the illegitimate state of Israel." It adds that entertainers will be removed from the list after they have made a "substantial financial donation to the Palestine Liberation Organization."

The bogus commission's New York address and telephone number in the letter are those of B'nai B'rith.

"It's rather bizarre," said Lehrer of the letter. "It's typeset. It looks fairly authentic."

The United Nations does maintain a roster of performers, academics and athletes who have been to South Africa, "presumably because they want to influence them not to participate in events in South Africa," said Giuliani.