Freeh told a news conference that the investigative team run by his law firm would examine gaps in Penn State's ``control environment,'' oversight and culture that allowed years of alleged abuse to go undetected and unreported.
``The scope of our work will be broad, covering a lengthy period of time,'' Freeh said.
Jerry Sandusky, a former assistant football coach at Penn State, was charged this month with multiple counts of sexually abusing eight young boys over a 15-year period. In a nationally-televised interview, Sandusky denied he abused the boys and said he is not a pedophile.
Two former university officials were charged in an alleged cover-up. All three have stated they are innocent.
The board of trustees fired legendary football coach Joe Paterno and Penn State's president for failing to tell police about the abuse once they learned of it.
Multiple investigations have been launched into what led to Sandusky's alleged crime and the university's response, including the one by the board of trustees that has now engaged Freeh and his law firm.
``We have to do an investigation that is perceived by everyone as fully impartial and comprehensive,'' said Ken Frazier, chairman of the trustees' special committee.
Freeh, who was FBI director from 1993 to 2001, has no previous connection to the university.
``The scope of his work will be expansive, and he is free to take his work to whatever conclusions he deems appropriate,'' Frazier said, adding that no one, including the trustees, will be exempt from the review.
Some have criticized the trustees for being blind-sided by the grand jury report into Sandusky's alleged crimes and the role that university officials might have played in covering them up, even though the existence of an investigation was reported earlier this year.
There is no specific time-frame for Freeh to complete his investigation and the findings and recommendations will be made public.
Freeh said investigators he has assembled include former FBI agents and prosecutors with decades of experience, including some with experience in pedophile cases.
The team has established its own toll-free hotline and email address for tips relevant to the case.