OSHKOSH (NBC 26) — Forty years ago, two teenage boys made a chilling discovery in the Wolf River near Winneconne — a human skull that would become one of Wisconsin's most enduring cold cases. Today, investigators say they're closer than ever to solving the mystery of who she was, thanks to breakthrough advances in DNA technology and genealogy research. Watch the full broadcast story here:Investigators closer than ever to solving 40-year-old cold case after skull found in Wolf RiverLieutenant Chris Braman of the Winnebago County Sheriff's Office has been working this cold case for 15 years. For decades, all investigators had to work with was the skull itself. If you have Irish or Northern English ancestry and think you might be connected to this case, investigators want to hear from you.