A federal appeals court Friday upheld the 2009 conviction and 50-year prison sentence of Minnesota businessman Tom Petters, who was found guilty of orchestrating a $3.7 billion Ponzi scheme.

The Eighth U.S. Circuit Court of Appeals ruled that Petters got a fair trial.

A three-judge panel rejected defense claims that the U.S. District Judge Richard Kyle prevented his attorneys from presenting a complete defense by restricting their ability to question a key prosecution witness, Larry Reynolds, a convicted felon and disbarred lawyer who was in the witness protection program, about his links to organized crime.

The panel also said the judge acted properly when he rejected proposed jury instructions that would have highlighted Petters' claims that he was an unwitting participant in a fraud conceived by others, and that he acted in good faith on advice from his attorney.

It ruled that the judge did not err by denying a change in venue due to the extensive media coverage the case generated. The panel also rejected defense claims of procedural errors in Petters' sentencing.

A jury found Petters guilty of 20 counts of wire fraud, mail fraud, money laundering and conspiracy.