The neonatal nurse Lucy Letby became notorious in the United Kingdom when she was found guilty of doing the unthinkable. In 2023, Letby was convicted of the murder of seven babies and the attempted murder of an additional six infants (a seventh charge for attempted murder came later). That made her one of the most prolific female serial killers in the U.K. But a new Netflix documentary, The Investigation of Lucy Letby , seeks to shed new light on the trial and challenge our understanding of