Peterson is charged with Savio's 2004 murder.
On Monday, a judge ruled both the defense and prosecutors can have access to two previous expunged court files.
Sources tell ABC7 that the two court filings are of misdemeanor battery cases filed against Savio in 2002.
According to published reports, the charges were filed by Peterson, and Savio was acquitted in both cases.
Peterson and Savio were married at the time.