In 1993, 19-year-old Sean Ellis was sentenced to prison for a crime he didn’t commit. He served 22 years for the murder of Boston Police Detective John Mulligan, who was shot multiple times in the head as he slept in his private vehicle while parked in a drugstore lot in Roslindale MA. At the time of his murder he was on a paid detail. It was revealed after his death that Mulligan was part of a four-man crime spree within the Boston Police Department. While watching TV in prison, Sean saw a Boston-based criminal defense attorney, Rosemary Scapicchio, who was defending another wrongfully convicted young man. Eighteen months after Sean wrote to her, Rosemary went to see him at the correctional facility where he was serving his sentence and decided to take his case. Rosemary reviews the challenges she faced and obstacles she overcame to finally get justice for Sean nearly 30 years after his conviction. This case was featured on the Netflix docuseries Trial 4, released on November 11, 2020.