Here are three of the biggest ones:

1. How big is this scandal?

The New York Daily News reported Sunday that federal authorities believe Donaghy will cooperate with investigators and possibly name other officials or players involved in the scandal. Stern has already come out publicly and said that Donaghy was the one and only referee under suspicion of affecting the outcome of games he officiated, but if the opposite is true and even more referees are involved, Stern's credibility will take another enormous hit. The Daily News said Donaghy has hired former federal prosecutor John Lauro, who specializes in representing whistleblowers, as his defense attorney.

2. When was the NBA informed that Donaghy was under investigation by the FBI?

The Denver Post reported Sunday that the answer to that question is January, which, if true, would mean the NBA allowed Donaghy to continue refereeing games, including playoff games, despite knowing he might be crooked. Who in the league office signed off on that?

UPDATE: The New York Times reported Monday, quoting two anonymous sources who had been briefed on the investigation, that the NBA had no knowledge of Donaghy's betting and questions as to whether he influenced the outcomes of games until after the season.

Also, the AP is reporting today that a person with knowledge of the FBI investigation, speaking on the condition of anonymity, said the NBA was unaware of the FBI investigation until after the NBA Finals.

3. What about all the red flags?

According to data compiled by Stats LLC and reported in the New York Post, Donaghy led the NBA in technical fouls called, whistling 177 of them -- 20 more than anyone else. Donaghy also ranked fourth in blowing personal fouls; was third in ordering free throws and second for fouling out players for the 2006-07 season.

The NBA is meticulous in gathering data on its referees and the calls they make, and if it had a referee calling an inordinate number of technicals, you'd expect they'd speak to Donaghy about it, no?

Also, the Post reported that NBA officials knew that Donaghy was gambling on football and ordered him to stop.

Further, the New York Times reported Sunday that since Jan. 1, Donaghy refereed in 11 games in which the consensus Las Vegas line moved two points or more: "The team on which bettors wagered heavily enough to move the line that far won seven of those 11 games. …

"On Jan. 15, the Philadelphia 76ers were originally favored to beat the Toronto Raptors by a point. Bets came in so heavily on the Raptors that they eventually were favored to win by a point instead. The Raptors won in a blowout, 104-86.

"Two nights later, so much money was bet on the Phoenix Suns against the Houston Rockets that the consensus Las Vegas line, which opened with the Suns favored by 4½ points, moved to 8 by tip-off. The Suns won by 9, 100-91."