The 2010 national champion Auburn Tigers were gripped by an epidemic of synthetic marijuana use that led to a rash of failed drug tests and a decision at the highest levels of the university's athletic department to keep the results confidential, ESPN has learned.

A six-month investigation by ESPN The Magazine and "E:60" into the spread of synthetic marijuana at Auburn reveals that a dozen students on the football team, including its star running back, Michael Dyer, failed tests for the designer drug.

The school did not implement testing for the drug until after it won the national championship in January 2011, and as many as a dozen other seniors who used synthetic marijuana were never caught, the investigation also found.

The drug -- also referred to as "spice" -- has been linked to paranoid delusions, hallucinations, and, in rare cases, deaths.

In one extreme case, a freshman tight end, Dakota Mosley, failed seven consecutive weekly tests for the drug, but never was punished. (He was suspended for three months in a separate incident after he tested positive for marijuana.) The Arkansas native says he learned he'd failed a sixth test on the same day he was scheduled to meet with NCAA investigators to discuss a probe into potential recruiting violations.

Instead of being kicked off the team, Mosley was brought into then-coach Gene Chizik's office and told he could keep his spot on the team.

"The whole time, I was thinking, 'They can't do nothing about the spice,' " Mosley told The Magazine and "E:60."