In March 1960, three middle-aged women from the Chicago suburb of Riverside stepped out of the local lodge at Starved Rock State Park, which sits along the Illinois River, for their first hiking excursion of a planned four-day trip. Frances Murphy, 47; Lillian Oetting, 50; and Mildred Linquist, 54, who were close friends and all attended the same Presbyterian church, wore their galoshes for the slippery winter hike.