NEW YORK — How much Tim Donaghy profited from his betting scheme, and how far he went to do so, still isn't known.

This much is certain: Donaghy wagered on games he officiated, and he did it longer than previously thought.

The disgraced former referee started betting on NBA games in 2003, long before he began tipping off high-stakes gamblers with inside information and recommending which teams to bet on — with a reward of $5,000 if his picks hit.

The stunning allegations emerged Wednesday as the Delaware County, Pa., native pleaded guilty to two felony charges in a scandal that rocked the league and tarnished the integrity of the sport.

"By having this nonpublic information, I was in a unique position to predict the outcome of NBA games," Donaghy, standing ramrod-straight with his hands clasped in front of him, told the judge in a Brooklyn courtroom.

Donaghy, , who was released on $250,000 bond, faces a maximum of 25 years in prison when he is sentenced Nov. 9 for conspiracy to engage in wire fraud and transmitting betting information through interstate commerce. He also must pay a $500,000 fine and at least $30,000 in restitution to the government.

Still, many questions remain. Authorities did not spell out specific games that Donaghy officiated and placed bets on, nor would they say if he made calls during the game to help a team cover the spread.

Commissioner David Stern said the NBA would "continue with our ongoing and thorough review of the league's officiating program to ensure that the best possible policies and procedures are in place to protect the integrity of our game."

Defense attorney John Laura told The Associated Press that Donaghy was "relieved this part of the proceeding is over and we look forward to completely resolving this matter in the coming months."

"Tim deeply regrets his involvement in this matter and especially the pain it has caused his family, friends and co-workers," Laura said.

The plea had been widely expected in recent weeks, but court documents released Wednesday revealed new details about the depth of the scandal.

The 40-year-old Donaghy, a graduate of Cardinal O'Hara High School in Springfield, Pa., and Villanova University, began placing bets on NBA games in 2003, court papers say. Starting last December, he began giving gambling associates sensitive information, including which crews would officiate games and how the various officials and players interacted.

His actions "compromised his objectivity as a referee because of his personal financial interest in the outcome of NBA games," the government said.

It was highly lucrative for Donaghy. While in Toronto, Phoenix and Washington, D.C., to referee games earlier this year, Donaghy received thousands of dollars in cash payoffs from the gamblers, authorities said.

In one exchange, according to court papers, Donaghy provided a tip about an NBA game on Dec. 13, 2006. That same day, he worked a 76ers game in Philadelphia against the Boston Celtics.