The NBA had hired a private investigator over a year ago to investigate referee Tim Donaghy's gambling habits after suspicions arose. The investigator interviewed Donaghy's neighbors and friends, learning that he gambled regularly, including at a casino in Atlantic City. Despite this, the NBA allowed Donaghy to continue refereeing games throughout last season. Donaghy is expected to surrender this week on federal charges related to betting on NBA games, including some he officiated. While investigators have not found evidence he intentionally influenced games, they believe he leaked confidential information to gamblers. The case has raised questions about games Donaghy refereed.