Former Westar Energy CEO David Wittig has lost another round in his fight to avoid returning to prison over a 2003 bank fraud conviction.

In June, a three-judge panel of the 10th U.S. Court of Appeals in Denver upheld a 24-month sentence for Wittig.

His attorneys asked the entire 12-member court to review that decision. This week, the court decided 6-5, with one judge not participating, against it.

Wittig served more than a year in prison before being released on appeal. He could appeal to the U.S. Supreme Court.

He was convicted of loaning $1.5 million to a former Topeka banker, then helping him hide the transaction.

In a separate criminal case, prosecutors alleged Wittig tried to loot Westar while running the utility.