The University of Tennessee says they found no evidence that Greg Schiano helped cover up child rape during his time at Penn State ... but they're still not explaining why they backed out of hiring him as the Vols head football coach.

FYI, Schiano was reportedly signed to be the next head coach -- but some students and supporters lashed out over the decision due to claims Schiano knew about the horrific things Jerry Sandusky was doing to children and didn't report him to police.

Schiano has denied covering up anything -- and said he never had any knowledge about Sandusky's disturbing crimes. Yahoo! Sports' Dan Wetzel explained where the allegation stems from.

Still, many have speculated that outrage over the Penn State connection is what led to Tennessee backing out.