On the day she was murdered, Myrtle Underwood Cook boasted to local authorities about new evidence of a major bootlegging ring operating out of the Rock Island train depot behind her house in a small farming town in eastern Iowa. Then, as she sat at her parlor window sewing, she took a single slug through the heart. She was president of the local temperance union; her killing made the front page of the New York Times. The next day her funeral...