Who is Lisa Westin from Presumption of Guilt and what is their importance?

Lisa Westin is seven-years-old girl, and she lives at SCCH. Jimmy is her older brother. When Jimmy doesn't return from Beth's house, Bill enlists Lisa as Jimmy's replacement in the crime ring. Lisa is the one that Bill gets to deliver the bomb package to the post office for delivery to Beth's house. Eventually, Jake and Lynda adopt Lisa when they adopt Jimmy.