A Times investigative reporter, Kim Barker, revisits the murder of Shelli Wiley — a long-unsolved case from Kim’s time in high school. She reaches out to Shelli’s family to understand why the police arrested a man named Fred Lamb for Shelli’s murder in 2016, and why prosecutors abruptly dropped the charges against him. Our newest podcast, “The Preventionist” is out now. Search for it wherever you get your podcasts.To get full access to this and other Serial Productions and New York Times podcasts on Apple Podcasts and Spotify, subscribe at nytimes.com/podcasts.To find out about new shows from Serial Productions, and get a look behind the scenes, sign up for our newsletter at nytimes.com/serialnewsletter.Have a story pitch, a tip, or feedback on our shows? Email us at serialshows@nytimes.com