Prosecutors spoke to reporters Wednesday evening about their appeal, which could delay the trial for several months.
Will County State's Attorney James Glasgow says he consulted with legal experts, including DuPage County State's Attorney Joe Burkett. Glasgow said he was ready to go to trial but wanted to make sure he could do everything he could do to make sure he would have evidence available to him.
Trial Judge Stephen White made a decision to bar certain hearsay statements-- which are third-party witnesses. According to sources, White is not allowing most of the statements.
"I only get one trial. There's a concept called double jeopardy. I'm obligated as the state's attorney of Will County to make sure that when I go into court, I have all the evidence that I can possibly garner," Glasgow said.
Contrary to what Drew Peterson's attorneys say, Glasgow says he was ready to go to trial-- even without the crucial hearsay statements. But a recent Illinois Supreme Court ruling prompted his decision to appeal. In that case, the court upheld a conviction of a Naperville man who killed four family members and rejected suspect Eric Hanson's arguments that hearsay statements from his sister should not be allowed.
Prosecutors say that means hearsay should be allowed in the Peterson case, too.
"I filed this appeal because there is evidence that I believe we should have available to us, and we're going to ask the appellate court to consider that under the Hanson case," said Glasgow.
"It means the state has declared that, absent this questionable, unconstitutional, and I think immoral, hearsay, they don't have a case," Peterson's defense Attorney Joel Brodsky said.
Drew Peterson is charged with killing his third wife, Kathleen Savio.
Glasgow responded Wednesday to reports that defense attorneys have called him a chicken.
"These kinds of comments about chickening out, anybody that knows me, I have been in this business for over 30 years. There is not a single person that would call me a chicken. It's just not going to be done," Glasgow said.
Drew Peterson's attorneys see the delay a big opportunity to get their client out of jail.
"When the state files an appeal, which actually says they don't have a case because of the judge's rulings, that means they don't have evidence. They don't have a case. They don't have sufficient evidence. When a state doesn't have sufficient evidence, they shouldn't hold the defendant in jail. That is not just me talking that. It's the Supreme Court rule," said Brodsky, the lead defense attorney.
"Judge White is going to follow the rules set by the Supreme Court. The Supreme Court says, when there is an appeal by the state, the defendant gets out of jail absent extraordinary circumstances. There are no extraordinary circumstances in this case, unless being Drew Peterson is an extraordinary circumstance," said Brodsky.
When asked if the extraordinary circumstance could be that Peterson is charged in the murder of his third wife and is a person of interest in the disappearance of his fourth wife, Brodsky said:
"I was talking to my co-counsel, Joe lopez today, and he had three prior homicide cases where the state has taken these appeals and the defendant was released the appeal."
Brodsky said he had not yet talked to client Drew Peterson about Wednesday's developments.
"I'm on my way right now to give him the good news," Brodsky said.
Peterson has pleaded not guilty to first-degree murder in Savio's death and has denied involvement in the disappearance of his fourth wife, Stacy Peterson, who has not been seen since October 2007.
Savio's death originally was ruled an accident after her body was found in an empty bathtub. Her body was exhumed after Stacy Peterson's disappearance, and Savio's death was then ruled a homicide.
Peterson was arrested and charged in Savio's death in May 2009. He's been named a suspect but not charged in Stacy Peterson's disappearance.
Prosecutors have filed a motion to present arguments to keep Drew Peterson in jail. Both sides likely will be in court Thursday morning.
ABC7 Chicago had a chance to talk to Kathleen Savio's brother, Nick Savio. He says he is disappointed in the latest legal action and that he is fearful Peterson might get out of jail.
"I think it's a travesty, not only to our family, but to Stacy's family. This guy goes on TV and jokes about people's pain," Nick Savio told ABC7 Chicago.
ABC7 also spoke with Pam Bosco, a spokesperson for Stacy Peterson's family. She says she supports the prosecution's action to appeal but is also concerned about Drew Peterson possibly being out of jail.
"I can't imagine being a family member right now for any of Kathleen's family and have this man walk the streets again," she said.
During a hearing earlier this year to determine what hearsay evidence a jury would be allowed to hear, several witnesses testified Savio told them she feared Peterson would kill her and had even sneaked into her house and held a knife to her throat and threatened her life.
They also presented witnesses who told of conversations they had with Stacy Peterson, including a pastor who testified Stacy told them she had helped Peterson concoct a fake alibi the weekend Savio's body was found.
(The Associated Press contributed to this report.)