Rep. Mervyn M. Dymally (D-Calif.) alleged yesterday that two continuing trials of members of the Black Hebrew religious sect are part of a political conspiracy by the U.S. and Israeli governments to destroy the group because "it is an irritant to the Israelis."

Dymally, who made a surprise appearance in U.S. District Court Wednesday to testify as a character witness for one of the defendants, ridiculed the federal prosecutors' portrayal of group members as participants in a nationwide, multimillion-dollar crime ring.

"Small religious groups are not popular with this administration, that's all," Dymally said. "They want everybody to line up and follow Jerry Falwell," the evangelist and founder of the Moral Majority.

Assistant U.S. Attorney Timothy J. Reardon III, who is acting U.S. attorney while Joseph E. diGenova is on vacation, said he could not comment on Dymally's contention of a conspiracy by the two governments "since the matter is at trial."

Dymally, a three-term member of Congress and a former lieutenant governor of California, has taken a strong interest in the trial of six Black Hebrews charged with conspiracy in connection with an alleged welfare fraud scheme and a second trial of nine other group members, including the group's U.S. leader, on charges of trafficking in stolen airline tickets, credit card fraud and falsifying passports.

Dymally said he has kept abreast of developments in the 4 1/2-month-long racketeering trial -- the longest trial in recent history at the U.S. District Court here -- through Claudette Johnson, a local business consultant who describes herself as an assistant to Dymally and has sat through much of the trial, taking notes.

Dymally said he agreed to testify on behalf of a defendant, Darlene Wilson, at the request of another member of the Black Hebrew sect because he found the welfare fraud charge against her to be completely unfounded.

"Here is a woman who is charged under RICO the federal racketeering statute for making a phone call to find out about welfare. My God, this is not Russia," Dymally said. "If that was a crime, everyone on my staff could be charged."

The legislator said he decided to take the stand on behalf of Wilson, who served as a volunteer in one of his reelection campaigns, at the request of another member of the Black Hebrew group.

Dymally explained his interest in the trials as a part of his overall concern about persecution of religious or political groups.

"Look, I'm a religious purist. I have gone to Moscow to plead the case of the refusenik Jews, gone to political prisoners, gone to Korea to plead the case of political dissidents," he said.

In the case of the Chicago-based Black Hebrews, who believe that they are descended from the original 12 Hebrew Tribes and are the rightful inhabitants of Israel, Dymally said he saw "a definite link" between the trials here and the arrests of sect members in Israel for working without proper permits. "It's an attempt to break them up, that's all," Dymally said.

The member of Congress said he was not arguing that all the defendants in the trials here are innocent of criminal activity. But he contended that the Justice Department is treating them "like Mafiosos" and is engaging in "overkill."

Dymally also suggested, as he did on the witness stand, that it was not wrong for Black Hebrews to use false names to obtain passports to gain entry into Israel to join an estimated 1,500 members of the group who have immigrated there from the United States.

Because the Israeli government has barred further immigration of Black Hebrews, "they had to do this to get in to see their families," Dymally said.

The Black Hebrews have tried to argue either on their own behalf or through their attorneys that they are victims of religious prejudice, but Chief U.S. District Judge Aubrey M. Robinson Jr., who is presiding over both trials, has refused to admit their arguments.

Prosecutors and defense attorneys presented closing arguments yesterday in the welfare fraud trial. The jury was to begin deliberations this morning.

Prosecutors in the racketeering trial have asked Robinson to order jurors, now in their sixth week of deliberations, to report on what decisions they have reached thus far.

The indictment involves 68 separate counts and nine defendants, requiring the jury to make about 400 separate decisions of innocence or guilt. Staff writers Nancy Lewis and Edward Walsh contributed to this report.