On a snowy December night in 1990, 25-year-old Donna Ingersoll stormed outside and disappeared into the night after a heated argument with her boyfriend, leaving behind several important belongings and a twisted web of mysteries investigators have spent decades trying to untangle.For more than 30 years, Donna’s disappearance has weighed on the small town of Wabasha, Minnesota, as the passage of time has produced more questions than answers. But some recent developments have present-day investigators questioning everything they thought they knew about the case — and believing they’re closer than ever to cracking it.