The Justice Department and the FBI joined the investigation yesterday into allegations of wire fraud in a suspect winning wager, possibly worth $3.1 million, placed by a Baltimore man through a New York betting service.

The disclosure of the federal criminal investigation came even as racing industry officials announced an emergency program designed to close a betting loophole and restore "customer confidence.

"At the request of the New York State Police, this office, along with the FBI, is assisting in this matter," said U.S. Attorney James B. Comey in the Southern District of New York.

A federal law enforcement official said the Justice Department probe was initiated to determine whether the mail or wire transfers were used "to perpetuate fraud and steal money."

Stacy Clifford of the New York State Racing and Wagering Board said federal officials joined in the investigation as a result of "a collaborative decision" and that the U.S. Attorney's office would henceforward act "as the lead prosecutorial agency."

Until yesterday, the state board and the New York State Police had been leading the investigation.

The federal intervention came as an industry trade group announced a swiftly prepared three-part program designed to eliminate the time lapse that investigators suspect may have been exploited more than once. Churchill Downs officials later said they would take further steps to ensure against wager tampering.

Under the plan announced by the National Thoroughbred Racing Association, new computer software will be in place within 30 days to prevent tampering with wagers.

Tim Smith, a commissioner of the association, said the steps drawn up by a special task force would be implemented by the three multi-track operators - Churchill Downs, Magna Entertainment and the New York Racing Association - as well as the three largest tote companies.

Under the plan, tote companies will within 30 days complete the installation of new software to scan all wagering pools in connection with multi-race wagers after each leg of the wager.

In addition, the wagering operators will install software to record all bets placed by phone.

As an interim measure, Smith said, racing organizations will closely review winning wagers to determine whether any are "irregular or otherwise questionable."

Smith described the steps as "initial" and indicated further steps to increase security may be in the offing.

Both the industry actions and the growing criminal investigation were triggered following a Breeders' Cup Pick Six bet placed last month by Derrick Davis, 29, the owner of a Baltimore computer consulting company. Davis' winnings were immediately put on hold, and he has yet to collect his winnings.

A former Drexel University classmate of Davis', Christopher Harn, also 29, of Newark, Del., was fired from his job with Autote, the company that processed the bet. Neither Harn or Davis graduated from the Philadelphia school, but they were fraternity brothers.

Daniel Conti, Harn's attorney, said yesterday that he remained convinced of his client's innocence. Davis' lawyer, Steven Allen, declined comment on the Justice Department statement. He has previously stated that his client did nothing wrong.

In addition to the Breeders' Cup race, investigators are looking into two bets placed earlier by a third Drexel fraternity brother, Glen DaSilva of New York. DaSilva placed suspect bets on races at Balmoral Park and Belmont Park early last month.

DaSilva has been unavailable for comment. Like Davis, the former Drexel student has been operating a computer business.

None of the three fraternity brothers has been charged.

Investigators suspect that in the questionable transactions, the bets may have been altered after the races but before the actual bets were electronically transmitted to the hub where the races were run.

Following the NTRA announcement yesterday, officials of Churchill Downs said they were initiating further steps to enhance security, including closing off and locking in bets at least two minutes before each race begins.

Donald Groth, chairman of the Catskill Off-Track Betting Corp., the company Davis used to place his bet, said the steps announced yesterday are likely to be the first in a series that will increase the cost of doing business.