WHITE PLAINS, N.Y. - A New York man who helped fleece gamblers out of hundreds of thousands of dollars in potential winnings in horse racing's biggest betting scandal acted because he was unemployed and troubled by drugs, his attorney said yesterday.

Glen DaSilva pleaded guilty yesterday in U.S. District Court here to conspiracy to commit wire and computer fraud and to money laundering. He is the second man to plead guilty in a case that came to light after the Breeders' Cup and that has rocked the thoroughbred racing industry. The third and last defendant, Derrick Davis of Baltimore, is expected to plead guilty to conspiracy to commit fraud today.

Christopher Harn of Newark, Del., pleaded guilty last month to conspiracy to commit fraud and money laundering.

At the time the crimes began late last year, DaSilva had lost his job as a computer technician for an accounting firm, was broke and used the proceeds of the scam to pay his living expenses, said his attorney, Edward Hayes of New York.

"He was misusing drugs at the time. I think that was part of the problem," Hayes said.

DaSilva acknowledged yesterday that he was undergoing drug counseling. He was on probation for a misdemeanor conviction for cocaine possession and last month tested positive for cocaine when he surrendered to authorities.

The three co-defendants, all 29 and all former fraternity brothers at Drexel University, were charged with stealing millions of dollars through several schemes that culminated in rigged bets on six races at the Breeders' Cup, run Oct. 26 at Arlington Park near Chicago.

Speaking publicly for the first time yesterday, DaSilva told U.S. Magistrate Mark D. Fox that Harn was the mastermind. Exploiting his job as a computer programmer for Autotote Systems Inc., a Delaware-based company that operates electronic betting equipment for many racetracks, Harn generated counterfeit betting tickets and later rigged bets. In exchange, he arranged to split the profits with his accomplices.

DaSilva said he was unaware that Harn was allegedly conspiring with Davis until after the scandal became public. "I was under the impression it was just me and Chris," he said.

The crimes began in November 2001, when Harn figured out how to search the computer records of Autotote client tracks for bets that had been won but not cashed. Harn asked DaSilva to cash hundreds of bogus tickets, worth tens of thousands of dollars, that Harn generated.

DaSilva took the tickets to automatic betting terminals at tracks in New York and New Jersey, and exchanged them for vouchers that he cashed at the pari-mutuel windows. He mailed Harn's share via overnight mail.

Harn, whose work included installing a touch-tone betting system for Autotote customers, in September told DaSilva to open an account at an off-track betting company in upstate New York that Harn knew did not record bets placed by touch-tone phone.

Harn then placed bets through DaSilva's account on Pick Four and Pick Six wagers, in which a gambler attempts to predict the outcome of consecutive races. Taking advantage of a delay in the transmission of data to the host tracks, Harn changed the bets after early races had been run.

"Chris placed the bets and changed the bets. I simply opened the account," DaSilva said of the two bets, which yielded $109,365.

To conceal the earnings, DaSilva mailed $31,500 worth of bank checks directly to creditors of Harn to pay off a car loan and mortgage - leading to the money laundering conviction.

Documents submitted in court yesterday allege that Davis joined the bogus ticket scam about six months ago and that he opened a telephone betting account for Harn to manipulate in October. It was the $3.1 million he stood to win on the Breeders' Cup that aroused suspicion. The payoff was frozen by investigators.

Davis' attorney, Steven A. Allen of Baltimore, said yesterday: "My client accepts full responsibility for his conduct. He was recruited by his friend, Chris Harn, who devised this scheme. Mr. Davis had a minor role in the events and is truly sorry for having become involved."

Outside the courtroom, Hayes said his client hesitated to plead guilty and implicate Harn because of their friendship and because Harn has a wife and young child. Hayes proposed a joint guilty plea that would have saved both men prison time.

But Harn went ahead and struck a deal with prosecutors, agreeing to testify against his friends. That saved Harn prison time but extended DaSilva's likely sentence by a few months.

DaSilva is scheduled to be sentenced March 11. Sentencing guidelines, which give credit for a guilty plea, provide for 21 to 27 months imprisonment, according to prosecutors. He also may be fined up to $254,000 and ordered to make restitution of up to $200,000. However, Hayes said his client has no money.

Last month, a roommate threw him out of a New York apartment, and he now lives with his sister in Connecticut, court documents show.

DaSilva remains free on bond, co-signed by his parents, Fausto and Maria DaSilva of Florida.

"It's very frightening. His father and mother worked very hard to give him an education. It's a terrible thing for him to have disappointed his family," Hayes said. "He got involved in something he shouldn't have. He is going to have to take his medicine."