CHAPEL HILL — North Carolina's investigation into possible improprieties in its football program took another serious turn Thursday night with the announcement of possible academic misconduct. The allegations involve a tutor who formerly was employed by Tar Heels football coach Butch Davis.

Chancellor Holden Thorp, athletic director Dick Baddour and Davis explained the new twist at a news conference at the Kenan Football Center on campus.

Baddour said a player interviewed during the NCAA's investigation into possible improprieties with sports agents shared information about the academic situation that led to the second prong of the investigation.

Former athletic faculty representative Jack Evans and former faculty president Lissa Broome are heading the investigation, which Baddour said the NCAA agreed should be conducted by the university.

Thorp apologized to those who love the university as he announced the new findings.

"Academic achievement and fairness are at the heart of the University of North Carolina and our department of athletics," Thorp said. "We are treating this issue with the seriousness that you would expect from this university. We will straighten this out. We are still gathering information, but our hope is that the scope of this is limited."

Baddour declined to say how many players are involved, saying the investigation is ongoing. He said the improprieties existed outside the classroom but gave no further explanation on what that meant. A university source familiar with the investigation said it involves inappropriate help on papers the players were required to write for class. Davis explained that in three years in Chapel Hill he has employed five "academic coaches" or academic advisers for his son, some from inside the university and some from outside the university. His son, Drew, is 17 years old and the starting quarterback at East Chapel Hill High School.

"To be honest with you, I think we're a little surprised and possibly disappointed," Davis said of learning one of his former employees was involved, "but there's been no revelation as to the extent or exactly what has transpired."

A clause in Davis' contract says that if an NCAA violation occurs in the program that he reasonably should have known about, the university can fire him without owing him payment for the remaining years on the contract.

With the investigation now taking on what Baddour called a second prong, Thorp was asked at what point a lack of institutional control becomes evident.

"Right now I think that what we need to do is determine the facts," Thorp said. "We are still in the middle of that, so it's a little early for me to say what it is that would make me feel one way or another about that question."

Baddour defended the program's integrity, explaining in depth the education on rules and academic integrity that athletes at the school receive, and that he feels good about the school's academic support program.

Thorp said he has every confidence in the ability of Baddour and Davis to lead the university through the investigation.

North Carolina opens the season Sept. 4 with a nationally televised game against Louisiana State in Atlanta, but since July details of the investigation have overshadowed talk about the game.

An undisclosed number of players were interviewed when NCAA investigators visited campus July 12 and 13, and investigators conducted more interviews during a return trip earlier this month.

Defensive tackle Marvin Austin and wide receiver Greg Little were among the players interviewed. The investigation also involves associate head coach John Blake.

One potential violation of NCAA rules occurred when former North Carolina defensive tackle Kentwan Balmer paid for Austin and then-Tar Heels defensive tackle Cam Thomas to train in California in summer 2009. Thomas confirmed that Balmer paid for the trip, which may be construed as an extra benefit by the NCAA.

Thomas and Austin trained at Proactive Sports Performance in Westlake Village, Calif. That facility is where clients of California-based agent Gary Wichard of Pro Tect Management train for the NFL draft.

Blake, the North Carolina assistant coach, is a former Pro Tect vice president and a longtime associate of Wichard, who also is Balmer's agent.

With the investigation now taking a new turn, Davis pledged the full cooperation of the football team. And Thorp vowed to find out what happened.

"It's a privilege to put on the North Carolina uniform and represent this university," Thorp said, "and it's our job to make sure that the people who do so have earned that privilege."

ktysiac@charlotteobserver.com or 919-829-8942