Hannah Knowles

Hannah Knowles is a forensic toxicologist employed by the Massachusetts State Police Crime Lab who testified in Trial 2 Days 8 and 9. Her testimony centered on converting a 93 mg/dL serum ethanol reading from a Good Samaritan Hospital blood draw at 9:08 a.m. into a whole blood alcohol concentration, and then performing a retrograde extrapolation to estimate Read's BAC at the time of the incident — producing a range of 0.14–0.28%. Her cross-examination by defense attorney David Yannetti extended across two days and focused on the reliability of the hospital lab results underlying her calculations and the assumptions built into her extrapolation methodology.