When the journalist and podcaster Tessa Kramer began a profile of the forensic scientist Mary Jane Burton, she had every reason to believe the woman was a hero. Following Burton’s death, in 1999, scraps of evidence she had taped to case notebooks in the 70s and 80s were found in the Richmond, Virginia, crime lab where she had worked. The evidence was re-tested for DNA and ended up exonerating 13 men imprisoned for violent crimes they did not commit. The story’s arc seemed clear. Kramer and her reporting partner, Sophie Bearman, would interview some of the grateful exonerees, talk to former colleagues, and assemble a complete picture of Burton, about whom little was known. That is, until Kramer spoke to a former trainee of Burton’s named Gina Demas, who had seen so many mistakes and problems with her mentor’s methodology that she blew the whistle on her. Once Kramer pulled the Demas thread, more followed, and the Burton-as-angel narrative unraveled. It took a ton of research, making this a 12-episode podcast, but it’s addictive and full of odd little nuggets. —Lisa Henricksson