Oral arguments were heard Tuesday in the appeal of a former Gary boxer's two life sentences for conspiring to distribute cocaine.

Charles "Duke" Tanner's hearing in Chicago's 7th U.S. Circuit Court of Appeals was rescheduled at the last minute from the original date of today. Tanner's defense lawyer, Andrea Gambino, did not return calls for comment.

Tanner was undefeated in his professional boxing career with 10 knockouts, according to court documents, before he was arrested in 2004.

Tanner and his brothers allegedly were part of a cocaine drug ring and the Renegades street gang, according to court records. Tanner was arrested after a criminal informant arranged for a fake cocaine transaction with the athlete in a Walgreens parking lot.

Now 30 years old, Tanner has been serving two concurrent life sentences in Terre Haute, according to the Federal Bureau of Prisons and court records.

Gambino argued in her appellate filing that Tanner's life sentence for a first-time offender in his 20s was "disproportionate in the extreme and manifestly unreasonable." She also claimed, among other arguments, that introducing evidence of a gun found at Tanner's mother's home in 1999 was prejudicial because there was no evidence of to whom the gun belonged.

Tanner's former promoter, Malcolm Garrett, declined comment, and members of Tanner's family could not be reached.