After serving nearly 21 years in prison for murder, 46-year-old Derrick Hamilton this week became the 11th person in less than a year to have his name cleared by Brooklyn’s new district attorney. Ken Thompson’s central reform since taking office last January is the Conviction Review Unit (CRU). Staffed by 10 lawyers, the team’s priority, Thompson tells The New Yorker, “is to give freedom to people who were convicted during the…era of mass incarceration but don’t belong in prison.” 

One reason Thompson’s unit stands out, experts say, is that instead of relying on DNA evidence to exonerate the innocent, it reviews tougher cases where fault may lie in human errors like negligence, misconduct or judgment.

Hamilton, a father of five, has been out on parole since 2011. He maintained that he had been out of state when the 1991 murder occurred. As a result of Hamilton’s and a number of other accusations, the district attorney’s office has been reviewing more than 70 cases worked by discredited homicide detective Louis Scarcella, now retired.

Read more about Thompson’s CRU on The New Yorker.