The suit was filed by the estate of Kathleen Savio on behalf of Savio and Peterson's two sons.
However, both sons have filed paperwork asking to be removed from the lawsuit.
Savio, Drew Peterson's third wife, was found dead in a bathtub in 2004.
Originally ruled an accident, the case was reopened after Peterson's fourth wife, Stacy, disappeared.
Peterson was found guilty of first-degree murder in Savio's death on September 6, 2012.
