Peterson was arrested Thursday and appeared in court Friday.
Savio died in 2004.
Peterson's fourth wife, Stacy Peterson, has been missing since October 2007. No charges have been filed in her disappearance.
Report: Savio relative happy about Peterson arrest
May 10, 2009 (CHICAGO) The step-mother of Peterson's third wife tells the Chicago Tribune that she is happy Peterson has been arrested and charged with first-degree murder.
