Christy Mirack was a 25th elementary school teacher in Lancaster, Pennsylvania.  One morning in 1992, she didn't' show up for work.  Her principal was extremely alarmed, so he went to her apartment to check on her.  He got there and the door was open she had been assaulted and murdered.  What happened next was shocking.  A random man shows up to her school looking for her, her principal is interviewed, and the case goes cold for 26 years.  After advances in DNA testing the killer is found.  He stayed in the town the murder happened in the whole time.