The judge ruled this week to exclude much of that hearsay evidence. That decision prompted prosecutors to delay Peterson's trial on charges he murdered his third wife, Kathleen Savio, in 2004.
The law says, when the state files an appeal in their own case, the defendant must be released from jail unless the judge finds compelling reasons to hold that person.
Without explaining his decision, Judge Stephen White found reasons to keep Drew Peterson behind bars. It was a ruling that was more surprising to Peterson's lawyers than it was to Peterson.
Stung by the judge, Peterson's attorneys were confident, almost convinced their client would be walking out of jail Thursday, but Judge White said, "The court finds compelling reasons to keep Mr. Peterson detained."
The judge didn't get into specifics.
The former Bolingbrook cop told his defense team he wasn't surprised.
"He was always hopeful and optimistic. He didn't count on it, so he is ok. He wasn't devastated at all. He's just going back to the life he's been living the past 14 months," said Joel Brodsky, Peterson's defense attorney.
And in jail is exactly where the families of Kathleen Savio and Stacy Peterson want him.
"I'm glad he is not out. It would have been scary having him out," said Anna Doman, Kathleen Savio's sister.
"I wasn't worried he was going to get out, but the chance was there. But who would want a narcissistic sociopath out on the street?" said Cassandra Cales, Stacy Peterson's sister.
Peterson's possibility of release came after Will County State's Attorney James Glasgow delayed the trial by appealing Judge White's decision to bar most of the hearsay evidence prosecutors were hoping to use in the trial.
"I believe best interest of justice, and we will continue to pursue and use every legal tool available to us to ensure a successful prosecution in this case," said Glasgow.
The appeal process could take months. Defense attorneys argued keeping Peterson in jail would violate his constitutional right to a speedy trial.
While they are disappointed, the former Bolingbrook cop's attorneys say they are not defeated.
"We are confident in the long run. In the long run, Drew's gonna be acquitted," said Brodsky.
While she supports the decision to appeal, Stacy Peterson's sister Cassandra Cales is anxious for Peterson to be tried sooner than later. She says Peterson has not allowed her family to see Stacy and Peterson's two children.
However, depending on how the appellate court rules on the hearsay evidence, both sides could take that decision to the Illinois Supreme Court. The legal maneuvering could take up to two years,