SPOKANE, Wash. -

The chance of a retrial for former Spokane police officer Karl Thompson now lies in the hands of judges of the 9th Circuit Court of Appeals.

Thompson was convicted of violating Otto Zehm's civil rights and of making false statements in the case. Zehm died in 2006, after a violent confrontation with Thompson inside a North Spokane convenience store. He's serving just under five years in prison.

According to court documents, Thompson's attorneys are arguing for a re-trial over four main points. One being how jurors overheard discussions during deliberations that the City of Spokane was corrupt. But maybe the biggest argument was that prosecutors for the government withheld exculpatory evidence, depriving Thompson of his right to due process.

While Thompson sits in federal prison in Oregon his defense team is working to get him a new trial. On Monday in front of the 9th Circuit Court of Appeals they argued that the government withheld exculpatory evidence from an expert witness that could have changed the defenses strategy.

"Didn't have his exculpatory opinions that the video didn't show that there were baton strikes at those two areas, number one. I didn't have his demonstrations," said defense attorney Carl Oreskovich.

The defense argued that video expert Grant Fredericks' opinion on what surveillance video that night from the Zip Trip actually showed, was withheld by the prosecution. The trial court determined that Fredericks' evidence was exculpatory and that it was suppressed but that it was not material. The defense said it was, and that the evidence could have been used for cross-examining the prosecution's witnesses. Attorneys for the government said it doesn't matter since Fredericks was never called to testify.

Thompson's defense also argued that the district court abused its discretion by admitting evidence of Zehm's innocence at the time of trial. During the incident Thompson had reason to believe Zehm had been involved in a strong arm robbery, meaning jurors may have been led to believe that since Zehm wasn't doing anything wrong he wouldn't have resisted arrest or fought back.

One of the three judges will now write an opinion determining if Karl Thompson deserves a re-trial or not.