Suffolk DA Rollins files motion to end the long-running prosecution of Sean Ellis By Adrian Walker Globe Columnist,Updated March 17, 2021, 6:07 p.m. Email to a Friend âTo be at a point now to have my name cleared is truly emotional,â said Sean Ellis on Wednesday as he expressed gratitude to Rachael Rollins and his two defense attorneys.Pat Greenhouse/Globe Staff Suffolk District Attorney Rachael Rollins filed a motion Wednesday that could bring to a close the three-decade-long case of Sean K. Ellis, whose conviction for the murder of Boston police Detective John J. Mulligan became a cause celebre that raised major questions about police corruption and prosecutorial misconduct.