But as Federal and state investigators began to look into the case, they discovered what they say is a much larger conspiracy. Dozens of state legislators, lawyers and lobbyists were interviewed, and Ms. Casey said that several decided to provide evidence to the Government as part of plea agreements and immunity deals.

When the F.B.I. raided Mr. Wilson's office in November 1997, it became evident to the public that the investigation had grown substantially, and it began to affect state politics. Gov. Mike Huckabee railed against the Legislature, although many legislators accused the Republican Governor of capitalizing on the fact that all of those under investigation were Democrats. The two former senators named in yesterday's indictment, Michael Todd and Steve Bell, decided not to run for re-election, and in the most recent session, the Legislature passed a bill that outlaws a wide variety of practices that allowed lawmakers to benefit from state contracts.

If convicted on all counts, Mr. Wilson faces up to 90 years in prison and the end to one of the state's longest and most colorful political careers. Mr. Wilson, 57, entered the Senate in 1971 as a fiery left-of-center reformer from the northern town of Pocahontas, and frequently clashed with governors of both parties, including Bill Clinton. Once, while Mr. Clinton and the Lieutenant Governor were out of the state, Mr. Wilson -- then president pro tem of the Senate -- declared himself Acting Governor and temporarily fired Betsy Wright, Mr. Clinton's chief of staff. Many legislators said Mr. Wilson, gruff and quick with a profane quote, essentially ran both houses of the Legislature for years.

''He has been an extremely influential senator,'' said Roby Robertson, a public administration professor at the University of Arkansas at Little Rock. ''He came in as a maverick, taking on the establishment, and has always been one of the brightest people in state government. I have to admit, I was often very impressed with him.''

But the indictment paints a grim picture of a different kind of brilliance. Beginning in 1995, it says, Mr. Wilson set up a corporation that received state contracts to collect child-support payments. The corporation submitted phony billings, and two-thirds of the $546,000 received from the state was kicked back to Mr. Wilson, the indictment says, while other payments were made to Mr. Bearden, a Senator for 13 years.

In addition, it says, a Little Rock insurance company, Sedgwick James of Arkansas, paid Mr. Wilson $227,000 to be selected to administer workers' compensation claims for the Arkansas School Board Association. Mr. Wilson gave half the money to Burton L. Elliott, former director of the state Department of Education, according to the indictment. In a related scheme, it says that Sedgwick James conspired with Mr. Wilson and Tommy R. Venters, former executive director of the school board association, to have lawyers representing school districts pay Mr. Wilson $20 an hour for each hour they billed the state. Mr. Elliott and Mr. Venters were also indicted.

In all, the indictment says, Mr. Wilson received $1.38 million through the various schemes, an amount the government demanded be repaid. The defendants, charged with a total of 133 counts, will remain free on their own recognizance, Ms. Casey said, and are expected to be arraigned in mid-May.

Ms. Casey, who has been the Federal prosecutor here for about six years, said the investigation was one of the largest public corruption cases in state history.