Nine members of the Black Hebrews religious sect, whose 1986 convictions in connection with a multimillion-dollar international crime ring were overturned last summer on appeal, have entered surprise guilty pleas, ending one of the most expensive criminal prosecutions ever undertaken here.

The guilty pleas, entered during a private pretrial work session with their attorneys on Friday, mean that six of the men will not serve any additional jail time. Under the plea agreement, the other three men -- including the U.S. leader of the Black Hebrews, Warren Brown -- who had been sentenced to 10 to 30 years will now face maximum sentences of 15 years.

Also as a result of the plea agreement, federal prosecutors have agreed to drop charges against 13 other members of the sect and to recommend reduced sentences for two members who had agreed to testify for the government.

Chief U.S. District Judge Aubrey E. Robinson Jr., who had set a March trial date in the case, will sentence the men on Jan. 20.

The nine Black Hebrews who entered guilty pleas were convicted in July 1986 on federal racketeering charges for operating the crime ring, which trafficked in millions of dollars of stolen airline tickets and used bogus credit cards and worthless checks to purchase thousands of dollars of merchandise.

Proceeds of the crime ring were used to support the 3,000 to 20,000 members of the Black Hebrews who live in "extensions" in several U.S. cities, including Washington, Chicago, Atlanta and Dallas, and sect members in Liberia and Israel.

Members of the Black Hebrews group, known officially as the Original African Hebrew Israelite Nation of Jerusalem, believe blacks were a part of the original 12 tribes of Israel.

The men's trial, which was based on a 68-count indictment and stretched over more than five months, is believed to be the longest and -- at more than $1 million -- the most expensive ever in federal court in the District. Much of the expense was to pay court-appointed lawyers for each of the defendants. A second trial was expected to cost almost as much.

The jury's deliberations were marked by several unusual twists, including the dismissal of one juror and allegations of jury tampering. The convictions were overturned by the U.S. Court of Appeals July 7 on the ground that Robinson had erred when he dismissed juror Bernard Spriggs after Spriggs said he couldn't "go along with" the way the federal racketeering statute was written and "the way the evidence has been presented."

The three-judge panel said Robinson should have had Spriggs continue his deliberations and that Spriggs' dismissal denied the defendants possible verdicts in their favor.

Three of the men who entered guilty pleas on Friday face a total of 15 years in prison. They are Brown, also known as Prince Asiel, 56; James Stone, known as Yeriel, 39; and J.C. Vortis, known as Navee, 38. Vortis headed the Washington Black Hebrew extension and Stone was a top aide to Brown in Chicago.

Each of the three pleaded guilty to a single count of wire fraud and a single count of interstate transportation of a forged security. Brown, Stone and Vortis had all been jailed since mid-1985 when the charges were first lodged against them. Each of the other six men pleaded guilty to single counts with a maximum prison term of five years.

The men and the charges are Gerald Bethea, 43, known as Ben Kiel, wire fraud; Gregory Coles, 25, known as Rooakiel, interstate transportation of a stolen motor vehicle; Cordell DeBardelabeen, 27, known as Sadiekiel, interstate transportation of a stolen motor vehicle; Thomas Cavin, 30, known as Navaniel, wire fraud; Darryl Grissom, 28, known as Amatsyah, wire fraud; and Kevin Robinson, 28, known as Smiel, wire fraud.