The New York attorney general began an inquiry Tuesday into the prospect that employees of daily fantasy football sites have won lucrative payouts based on inside information not available to the public, asking two leading companies, DraftKings and FanDuel, for a range of internal data and details on how they prevent fraud.

Word of the inquiry came as the revelation that DraftKings and FanDuel allowed their employees — many with information not available to customers — to play at each other’s sites and win large amounts of money continued to rattle the sports world.

Some of the industry’s primary sponsors raised questions or distanced themselves from lucrative advertising and sponsorship deals. On Monday, both companies told The New York Times that they had temporarily prohibited their employees from playing in money games. In a statement Wednesday, FanDuel announced that it was permanently barring its employees from playing daily fantasy games on any site, and was prohibiting employees of other companies from playing on its site.

Major League Baseball, which owns a stake in DraftKings and has a sponsorship deal with it, said in a statement that it had a policy that “prohibits its own players and employees from participating in fantasy baseball games where money or something of value is at stake, and did not know that the situation was different at DraftKings.”