Since the early 2000s, a spate of forensics-focused TV shows and films have emerged on the pop culture scene. Years after Law & Order premiered in the '90s, shows like CSI, NCIS, and The Mentalist followed, trumpeting the scientific merit of analyzing blood-spatter patterns, reading facial and bodily cues, and using the latest fingerprint-matching technology to catch the bad guy.

Yet what these procedurals neglect to acknowledge is that many of these popular forensic techniques are deeply unscientific and entirely political. Spatter pattern-matching, firearms analysis, hair analysis, fingerprint and bite mark analysis — they’re all mostly bullshit with little scientific merit. Despite this, forensics have helped contribute to the wrongful convictions of thousands of people: a storytelling aid, prosecutorial smoke and mirrors, a courtroom PR tool to lend scientific verisimilitude to what is very often just circumstantial, hunch-based police work.

On this episode, we break down how popular culture depictions of forensics helps mislead viewers — and by extension jurors — into thinking forensics are science that proves guilt rather than what they really are: slick marketing collateral to help prosecutors convict someone they already think is guilty for other, nonscientific reasons.

We are joined by Aviva Shen, Senior Editor at Slate.