Three fraternity brothers being investigated in connection with a series of suspicious winning bets on thoroughbred horse races have been ordered to appear today in federal court, where they are expected to face conspiracy charges.

Attorneys for the three men say they have been told to report to the FBI office in White Plains, N.Y., at 8 a.m. today. From there, they will be transported to the U.S. District Courthouse for the Southern District of New York for an appearance before a magistrate.

A criminal complaint alleging conspiracy to commit wire fraud was filed under seal Friday, which gives prosecutors 30 days to indict the men or drop charges, according to one source involved in the case, who spoke on the condition of anonymity.

A brief hearing before a federal magistrate is expected, after which the men will seek to be released on bond, the source said.

One of the men, Derrick Davis of Baltimore, holds the winning tickets on the Ultra Pick Six for the Oct. 26 Breeders' Cup, a day of racing held this year at Arlington Park near Chicago. The $3.1 million payoff was put on hold by New York racing authorities. They launched an investigation of the wager, which Davis placed through a telephone service operated by Catskill Off-Track Betting Corp. of Pomona, N.Y.

Investigators became suspicious because of the composition of Davis' bet. To win a Pick Six, a bettor must select the top finisher in six consecutive races before any of the races are run. Davis picked the winner of each of the first four races, then bet on all of the horses running in the final two.

This raised concerns that the first four selections may have been altered in the computer system handling the wager before they were sent to the central hub in Chicago shortly after the fifth race.

Software engineer Christopher Harn of Newark, Del., was fired the week after the race by the company that processed the bets at its center in Newark. The company, Autotote, said he had the passwords and know-how to alter bets in the computer.

A third man, Glen DaSilva of New York, attracted the attention of investigators for a pair of bets placed earlier last month through Catskill's phone betting service. The bets, both involving multiple-race wagers and following the same pattern as Davis', yielded $100,000 in winnings.

All three men are 29 years old and attended Drexel University in the early 1990s and lived in the Tau Kappa Epsilon house.

"It is my client's position that he did nothing wrong," said Steven A. Allen of Baltimore, Davis' attorney. "There is no evidence that anything illegal took place and we're confident that at the end of this matter the conclusion will be that he is innocent of any wrongdoing."

Daniel Conti of New York, who represents Harn, said he was told to surrender his client this morning. "I don't know any details of the charges," he said.

He said his client did nothing wrong and will plead not guilty.

Rae Koshetz, an attorney in the office of Edward W. Hayes, who is representing DaSilva, said their client is also innocent and will be in New York today as ordered. "The burden is on the prosecutor to show a crime has been committed," Koshetz said.

U.S. Attorney James Comey and the Federal Bureau of Investigation entered the case on Friday after a two-week long investigation by the New York Racing and Wagering Board and the state police.

Also on Friday, the National Thoroughbred Racing Association announced a plan to prevent tampering with wagers. Among other things, new computer software will be put in place soon.