Authors Phil and Sandy Hamman will discuss their books "Gitchie Girl" and "Gitchie Girl Uncovered." Five teenagers gathered around a campfire at Gitchie Manitou State Preserve on Nov. 17, 1973. By morning, four had been murdered. The lone survivor became known as the "Gitchie Girl." For more than 40 years, the events of what happened remained a mystery to all but a few. Then the lone survivor broke her silence. The books focus on the survivor's life and the hunt to find to killers. The Hammans will not be present at the program, but video conferencing will be used so people will be able to see, hear and talk to the authors. The program is free and everyone is invited to attend. The books will be sold a the Heritage Store at the Cultural Heritage Center.