Susan Savio Doman spoke at the Soup Bowl Event in Madera to tell the tragic story of her sister's murder by her husband, Drew Peterson.
Peterson, a former Illinois police officer, was convicted in September for killing Kathleen Savio.
The case gained national attention because Peterson is also suspected in the disappearance of his 4th wife.
Peterson's former sister-in-law is now telling the story to save other women from a similar fate.
Susan Savio Doman said, "I believe that she fought for her life. She reached out to everyone for help and no one helped her, so this is a story that may be able to help others in the same situation, but they may want to do things a little bit differently."
October is National Domestic Violence Awareness Month.
