Michelle Fournier's parents are suing for monetary damages on behalf of themselves and her 8-year-old son.
Prosecutors believe a contentious custody battle between Fournier and Dekraai over the child is the motive behind the shooting.
Scott Dekraai, 42, is accused of fatally shooting his ex-wife, Michelle Fournier, and seven other people last month. A ninth person was wounded in the shooting, but survived.
