CHAPEL HILL, N.C. — The investigation of North Carolina’s football program has expanded into possible academic misconduct involving players and a woman who also has worked as a tutor for coach Butch Davis’ son, school officials said Thursday night.

Athletic director Dick Baddour declined to identify the players or say how many may be involved, and he refused to specify what the possible violations may have been, saying only that they involved “a student tutor and student-athletes on the football team.

“We are looking into improprieties that existed outside the classroom,” Baddour said. “That’s about as close to that as I can get.”

The announcement came nine days before the No. 18 Tar Heels’ opener against No. 21 LSU in Atlanta, and roughly two months after the NCAA began an investigation into whether two key players — defensive tackle Marvin Austin and receiver Greg Little — received improper benefits from agents. Defensive line coach John Blake’s longtime friendship with California-based agent Gary Wichard also has drawn the NCAA’s interest.

Joint interviews conducted by NCAA and school investigators during that probe led them to a player who “raised an issue that we felt like deserved further consideration on our part.

While the investigation is centered on the football program, Baddour said that “we will certainly use the opportunity to take a complete look at everything that we’re doing in the academic support program.”