COLUMBUS, Ohio -- A tattoo parlor owner whose purchase of Ohio State football memorabilia triggered an NCAA investigation of the school pleaded guilty Tuesday to drug trafficking and money laundering charges.

The federal charges against Edward Rife didn't directly involve Ohio State, but the university first learned of the memorabilia sales through the federal investigation into Rife.

Football coach Jim Tressel resigned after it emerged he had known of his players' involvement with Rife and didn't report it to the NCAA or his superiors for more than nine months.

In December, star quarterback Terrelle Pryor and four other Ohio State players were found to have received cash and discounted tattoos from Rife in exchange for signed Buckeye memorabilia and championship rings. All were permitted by the NCAA to play in the Buckeyes' 31-26 victory over Arkansas in the Sugar Bowl, with their suspensions to begin with the first game of the 2011 season.

After the team returned from New Orleans, investigators found that Tressel had learned in April 2010 about the players' involvement with Rife. A local attorney and former Ohio State walk-on player, Christopher Cicero, had sent Tressel emails detailing the improper benefits, and the two ended up trading a dozen emails on the subject.

Tressel had signed an NCAA compliance form in September saying he had no knowledge of any wrongdoing by athletes. His contract, in addition to NCAA rules, specified that he had to tell his superiors or compliance department about any potential NCAA rules violations.

Sports Illustrated has reported that the memorabilia-for-tattoos violations stretched back to 2002 and involved at least 28 players.

Tressel, who won a national championship and seven Big Ten titles at Ohio State, resigned May 30. Pryor also has announced he's leaving Ohio State.