The allegations were made at a hearing today where Peterson's lawyers were asking for a reduction in their client's $20 million bond, according to the report. A judge refused to reduce the bond.
Assistant District Attorney John Connelly said after the new allegations were bared, "I believe the likelihood of a conviction is strong."
Prosecutors gavea preview of their case today and said Savio's death was staged to make it look like an accident.
The state also claims Peterson tried to solicit a hit on Savio in 2003, but did not elaborate. Prosecutors indicated they have evidence that would be presented in court.
In addition, the state told the court that Peterson knew fact of the case that only the killer would know.
On Thursday, police realized that were facing major obstacles in identifying the body found along an Illinois river bank near Peterson's home since the corpse is missing its head, arms and skin.
The office of Will County Coroner Patrick K. O'Neil said the body -- which many believe could be that of either Peterson's missing fourth wife Stacy -- was clad in only women's underwear and shreds of blue jeans that held a small amount of money.
Since the corpse lacks a head, hands or feet, it has complicated identifying the body through dental records or prints.
"The partial skeletal remains consisted of a rib cage, spinal column and partial left and right femur bones," the coroner's office said.
The lack of skin has made it more difficult to obtain DNA. A coroner and a forensic anthropologist are working together to confirm the gender of the corpse and are expected to test the bone marrow to try and identify the remains, sources told ABC News affiliate WLS's Amy Jacobson.
The coroner's office said it will take at least two weeks to obtain the DNA and determine its match.
They are also trying to determine whether the head was severed before or after death, O'Neil said. Police are also searching for the body's head and other body parts.
Though officials acknowledge the body could be someone else's the similarities between Stacy Peterson and another missing woman, Lisa Stebic, are numerous. Both are of similar height and weight and both have had Cesearan sections after giving birth. They also disappeared within months of each other.
The discovery Wednesday of the decomposing body near Peterson's Illinois home has the potential to blow huge holes in his claim that his fourth wife simply ran off with another man.
But Stacy Peterson wasn't the only local woman who disappeared in 2007. Lisa Stebic, a mother from nearby Plainfield, Ill., disappeared in April 2007.
"My honest feeling is hope the body is ID'd if it was Lisa or Stacy," Stebic's cousin Melanie Greenburg said. "I hope one of our families gets closure from this."
But the fact that the decomposing body was found less than a mile from a blue barrel could be significant, as Peterson's stepbrother told "Good Morning America" in March that he helped Peterson move a heavy blue barrel from the Petersons' home into their SUV shortly after Stacy Peterson disappeared.
"I know he killed Stacy," said Peterson's stepbrother Thomas Morphey.