JOLIET, Ill. (CBS) — Convicted murderer Drew Peterson goes back to court in Will County tomorrow, hoping to convince a judge to grant him a new trial, reports WBBM’s Regine Schlesinger.

After a five-week trial, a jury in Joliet convicted Peterson last summer of the 2004 murder of his third wife Kathleen Savio.

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Some of the jurors said what clinched their verdict was testimony from Harry Smith. He was the divorce lawyer for Peterson’s fourth wife Stacy who has been missing since 2007.

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It was the defense that called Smith as a witness. Now Peterson’s lawyers allege his fired attorney Joel Brodsky was responsible for that, but Kent Law Professor Richard Kling said he would be shocked if the judge threw out the verdict based on that.

“Defendants are not entitled to perfect trials they are entitled to fair trials and the fact a strategy backfires it is necessarily basis for getting a new trial,” said Kling.

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If Judge Edward Burmila denies the motion for a new trial, he could go right to sentencing with Peterson getting between 20-60 years in prison.