A subdued Stern said he felt betrayed by former referee Tim Donaghy, the target of a FBI investigation for allegedly betting on games, including some he officiated, over the last two seasons.

Stern said he believed no other officials or players would be implicated in the betting scandal.

Pausing often and carefully choosing his words during the packed, 1-hour, 10-minute news conference, Stern compared Donaghy to someone who's committed treason.

"I feel betrayed by what happened on behalf of the sport, regardless of how protective I've been," he said. "This is not something that is anything other than an act of betrayal of what we know in sports as a sacred trust."

Besides allegedly placing his own wagers, investigators also are examining whether Donaghy provided inside information to others, including referees' schedules, according to a person familiar with the investigation.

The FBI first contacted the NBA on June 20 to talk about a referee alleged to be gambling on games, and the two sides met on June 21, Stern said. Donaghy resigned on July 9, though Stern said he would have fired him sooner but was told it might affect the investigation.