A nationwide FBI dragnet reminiscent of Prohibition-era antimob crackdowns evidently has crushed a small but heavily armed neo-Nazi cell that issued a "declaration of war" against the United States.

The Federal Bureau of Investigation says a spate of arrests this winter and spring rounded up all but three of the suspected members of a white supremacist group thought responsible for a multistate crime spree last year that included counterfeiting, armored-car robberies, a synagogue burning, and the gangland-style murder of a liberal Jewish radio personality here.

On Monday, Justice Department officials in Seattle are expected to announce the indictment of about two dozen neo-Nazis under the federal Racketeering-Influenced and Corrupt Organizations (RICO) statute.

The government resorted to the racketeering law, normally used against organized crime and drug-trafficking operations, after it became clear that a series of violent crimes seemed to trace back to the same hate group.

FBI special agent Norman D. Stephenson told a federal magistrate in Seattle that the organization, variously known as The Order, The White American Bastion or Bruder Schweigen ("Silent Brotherhood"), evidently was acting out a Nazi fantasy.

He said the group's activities seem to have been inspired by "The Turner Diaries," a novel by white supremacist William Pierce of Arlington, Va., in which armed American Nazis overthrow the U.S. government and launch a nuclear attack on Israel.

The book portrays the Nazis as murdering prominent American Jews, an action reflected in the killing last June of Alan Berg, a liberal Denver radio personality. Police here say four members of The Order killed Berg with a spray of automatic rifle fire outside his town house.

As in the novel, the real-life neo-Nazis allegedly engaged in large-scale counterfeiting, not only to get cash but also to debase the currency and disrupt the Federal Reserve System, which the neo-Nazis believe to be controlled by Jews.

In congressional testimony this month, FBI Director William H. Webster said The Order represents the most violent manifestation to date of the racist, anti-Semitic philosophy reflected in the Ku Klux Klan and the American Nazi Party.

Webster said the FBI has arrested 26 members and supporters of the neo-Nazi cell. Another member, Robert Jay Matthews, died in a fiery gunfight with federal agents on Whidbey Island, Wash., in December.

The three members at large are Richard Scutari, one of the men thought to have been present at the Berg slaying, and former Klan members Randall P. Evans and Frank Silvia.

Federal charges have been brought against Order members in Philadelphia and several western cities. To consolidate the law enforcement effort, the Justice Department last fall empaneled a grand jury in Seattle to hear charges under the antiracketeering law.

Law enforcement officials say some neo-Nazi followers have cooperated with the government during the investigation despite a "death sentence" issued against any member who does so.

One Order member, Eugene Kinerk, hanged himself in a Boise jail cell the day after he testified before the Seattle grand jury. Kinerk left a note saying that Order members would have stalked him.

Among those called before the grand jury was Richard Butler, a nervous, thin-faced engineer who heads the Church of Jesus Christ-Christian and its proselytizing arm, Aryan Nations, both with headquarters in a heavily guarded compound beside a lake in the town of Hayden Lake, Idaho, about 80 miles from the Canadian border.

Butler is one of the leading advocates of the view that residents of the "white nations" of North America and Western Europe are the true descendants of the biblical tribes of Israel. He says that Jews and blacks are descendants of Satan.

Over the past decade Butler's Idaho compound, surrounded by barbed wire and "Whites Only" signs, has served as a home base for a disparate collection of neo-Nazi and Ku Klux Klan activists. Butler's "church" has worked for a decade to spread its supremacist views. Aryan Nations has an extensive catalogue of literature and paraphernalia ranging from century-old anti-Jewish tracts to plastic coffee mugs and key chains bearing the bright red-and-blue Aryan Nations seal.

Butler said in an interview last winter that several members of his group were ex-convicts whom he contacted in prisons. They formed the core of the group suspected of the Berg murder and several other crimes.

Working with Louis Beam, a Texas Ku Klux Klan member adept with computers, Butler last year started a computerized "bulletin board" to spread his hate message electronically. He also has sent instructions telling followers how to apply for broadcast time on the public-access portions of cable television systems.

Butler has not been charged with any crime related to activities of The Order.