The N.C.A.A. is conducting a wide-ranging investigation into the University of Tennessee’s football recruiting practices, according to interviews with several prospects, their family members and high school administrators. A significant part of the investigation is focused on the use of recruiting hostesses who have become folk heroes on Tennessee Internet message boards for their ability to help lure top recruits.

N.C.A.A. officials have visited four prospects and are scheduled to visit two others this week in an investigation covering at least three states. The inquiry is unusual in its scope and its timing. It is rare that the N.C.A.A. looks at this wide a swath of one university’s recruits before the players have signed with a program in February.

Tennessee Athletic Director Mike Hamilton confirmed that an investigation was under way but declined to elaborate.

“Typically, we do not comment on inquires that are in progress,” he said Tuesday night in New York.

Since Tennessee Coach Lane Kiffin took over in December 2008 after being fired as the Oakland Raiders’ coach, the Volunteers have committed at least six secondary N.C.A.A. violations  unintentional violations that provide minimal recruiting or competitive advantage.