Michelle Taylor sat at the defense table during her sentencing hearing in St. Augustine, Florida, listening to a trio of forensic chemists lay out the scientific evidence to prove what she’d sworn for years: She had not set the fire that burned down her house and killed her own son.

It was the last Friday in May, and the St. Johns County courthouse was mostly empty.

The expert witnesses each testified via Zoom, their faces appearing on a pair of large monitors inside the wood-paneled courtroom. None of the experts knew Taylor personally. But they knew chemistry. And each made clear that the case against Taylor had been based on junk science: faulty analysis by a state lab worker who detected gasoline in fire debris samples where there was none.