After hearing concerns from owners and fielding inquiries from top agents over the past several weeks, the NBA has opened an investigation into how free agency operated this summer, multiple league sources told ESPN.

The scope of the investigation is still being determined, but sources say it will likely focus on some of the earliest reported deals on June 30 -- the first day teams and representatives for free agents are technically allowed to speak. League officials are expected to begin scheduling interviews in the coming days as they seek to gather information, sources said. There is no timetable for its completion.

The urgency for this step grew out of the board of governors meeting earlier this month in Las Vegas, sources said. During the meeting, owners raised concerns about the flurry of deals that were completed within hours of the official start of free agency on June 30, with the belief that tampering rules may have been violated, sources said.

More than a billion dollars in contracts were agreed to in the first 24 hours of the new league year, making it likely that negotiations had begun and in numerous cases were finalized well before the official opening of free agency.

The league has the right to punish teams for breaking league rules during free agency with fines and -- although rare -- the loss of draft picks or even the voiding of contracts.

It is technically against league rules for players to tamper with each other and work together on transactions before the opening of free agency. However, the NBA has set a precedent that it wouldn't punish players because it is too difficult to police player-to-player communication.

This summer, Kawhi Leonard and Paul George appeared to work in tandem on a free agency-trade scenario that got them both to the Los Angeles Clippers. This looked to league observers like a high-profile case of players and their agents creating a transaction involving third-party teams.

The NBA's investigation may not lead to any formal punishments, but the information gathered could trigger rule changes to the free-agency system in the future.