Petersen, convicted in September 2012 of killing Kathleen Savio, called on three of his six former defense attorneys after initially employing an appellate lawyer provided by the state, the Chicago Tribune reported Friday.
The retired Bolingbroke police officer is serving a 38-year sentence for the 2004 murder of Savio and is the only suspect in the 2007 disappearance of his fourth wife, Stacy.
The appeal, expected to be filed within 90 days, will be based on several factors, including the admissibility of hearsay evidence and the competency of former lead defense attorney Joel Brodsky.
Will County prosecutor James Glasgow has said he expects the conviction to withstand appeals.
When he was sentenced in February, Peter screamed, "I did not kill Kathleen!" and insisted he was the victim of "rumors, gossip, outrageous lies and, most importantly, unreliable hearsay."
His legal team has argued former lead attorney Joel Brodsky botched his defense by calling divorce lawyer Harry Smith as a witness. Smith testified Stacy Peterson had told him Drew Peterson said he killed Savio.
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