Will County State's Attorney James Glasgow told reporters at a news conference Thursday night Peterson has been charged with two counts of first-degree murder in Savio's death, the Chicago Tribune reported. Glasgow said the arrest warrant provided for Peterson to be held on $20 million bail.
"I requested the $20 million bond because I felt this was as grave and serious a case as I've ever handled," Glasgow said.
He said a judge also signed a warrant for a search of Peterson's home.
Peterson, 55, has been the subject of widespread speculation in the case, in which Savio was found drowned in an empty bathtub in March 2004 with a gash in her scalp. An autopsy determined she had drowned and the coroner's office determined the death was accidental, but the case was reopened after the October 2007 disappearance of Peterson's fourth wife, Stacy, who is still missing.
Savio's remains were exhumed and a second autopsy concluded her death was a homicide.
Peterson's attorney, Joel Brodsky, told the newspaper he was unaware of the arrest early Thursday evening but another attorney for Peterson, Andrew Abood, issued a statement saying the former Bolingbrook Police Department sergeant continues to maintain his innocence in the death of Savio.
"Although he is disappointed with the decision of the state, he looks forward to the opportunity to once and for all prove his innocence in a court of law," the statement said.
Representatives of Savio's estate last month filed a wrongful death lawsuit against Peterson.
Peterson collects a $6,068 monthly pension from the police department, which suspended him after the disappearance of Stacy Peterson, the Tribune said.
Three of Peterson's four children have been placed in the custody of the Illinois Department of Children and Family Services and police were searching Thursday night for the fourth child, the newspaper said.