Who killed Tammy Zywicki? Over 30 years, zero answers
College student Tammy Zywicki vanished on Aug. 23, 1992, as she drove back to Grinnell College in Iowa from Evanston. Her body was found nine days later. And more than three decades later, her murder remains unsolved. CBS 2 Investigator Brad Edwards revisits the gruesome case, and the search for the killer that Tammy's family has never given up. Produced by Dylan Van Sickle and Adam Harrington.