WHO KILLED CYNTHIA JANE ALLEN?

According to https://www.websleuths.com/forums/threads/wi-cynthia-allen-17-marinette-11-june-1972.271276/, Cynthia Jane Allen was kidnapped on June 11, 1972 after dancing at the school Marinette Catholic Central, now dedicated to St. Thomas Aquinas and located at 1200 Main Street in Marinette, Wisconsin. The victim was supposed to return home at 90 N. Raymond Street, but was found dead on July 2, 1972