Paul Vathis, File, Associated Press
FILE - In an Aug. 6, 1999 file photo, Penn State head football coach Joe Paterno, right, poses with his defensive coordinator Jerry Sandusky during Penn State Media Day at State College, Pa. Sandusky is currently charged with more than 50 counts related to sexual abuse over a 12-year period.

STATE COLLEGE, Pa. — An Associated Press investigation into the Penn State child sex abuse case suggests that in addition to charges against former assistant coach Jerry Sandusky and two school officials, blame rests on the university as an institution and the entrenched traditions of now-fired head football coach Joe Paterno.

A team of AP reporters found that from the university president to department heads to janitors, too many knew of troubling behavior by Sandusky. But the circle of knowledge was kept very limited and very private.

The reporting team also uncovered new details about the Sandusky investigation and interviewed Paterno's wife, who vigorously defended her husband and asserted that his university superiors are responsible for any mistakes in the handling of a 2002 abuse complaint.