In a Facebook post, Cassandra Cales wrote that she has never given up searching for her sister and claimed to have photographs of Peterson's body in a sanitary and shipping canal.
A source told ABC7 the images show a full skeleton and the chances of Peterson's remains being intact after so much time are low.
Peterson was the wife of Bolingbrook police officer Drew Peterson. She went missing in October 2007.
A spokesperson for the Will County State's Attorney said they have followed every credible lead in the case.