WHO KILLED GLORIA FRIEDA RIEKEN?

As reported by https://www.websleuths.com/forums/threads/gloria-frieda-rieken-18-went-missing-in-november-1970-murder-unsolved.613286/, University of Minnesota Gloria student Frieda Rieken was killed around 9 November 1970 in a manner not confirmed by the autopsy. The body was hidden in a field at number 20692 of Keystone Road in Milaca, Minneapolis, one kilometer from St. Paul. The body was found following the outbreak of a