A Black man from St. Louis has served a decade in prison for a crime he swears he didn’t commit. The only evidence linking him to the shooting that resulted in a 25-year sentence was the testimony of a white police officer. But what neither he, his attorneys nor the jury that convicted him knew at the time was the officer had mistakenly arrested another Black man seven months earlier, using an illegal choke hold that ended in the man’s death. The officer also had a long history of racist posts on social media denigrating Black people.