In 49 other states, Joseph Sledge would still be in prison.

The North Carolina Innocence Inquiry Commission is the first full-time state agency dedicated to investigating post-conviction claims of actual innocence. “The innocence commission is the only one of its kind in the nation,” the executive director, Kendra Montgomery, told me. Other states have nonprofit organizations like the Innocence Project or think tanks with similar names, “but we’re the only state that has a government agency that is neutral to investigate these cases,” she said. 1,642 claims have been submitted to the commission since its creation in 2006; Sledge’s case marked the eighth exoneration.

Because it is a state agency, the commission has powers that other institutions lack. Investigators can compel testimony with subpoenas, for example, and gather other kinds of evidence for their cases. “The commission has the unique power, because we are a neutral, fact-finding state agency by statute, to collect and test physical evidence in criminal cases,” said Sharon Stellato, who led the commission’s investigation of Sledge. This ability can be decisive: In at least 18 cases, commission investigators were able to locate evidence that had been officially declared lost or missing by other state agencies. Three of those cases resulted in exonerations, while some others confirmed the convictions.

In Sledge’s case, investigators spent about 18 months examining the case before bringing it to a hearing. Other investigations lasted even longer. “Some take years, some take months,” Montgomery said. A convicted person must meet certain criteria to qualify for a commission investigation. First, the applicant must claim actual innocence of any criminal responsibility for the crime in question. Second, there must be credible, verifiable evidence of that innocence. This can include DNA evidence, like that which helped exonerate Sledge, or new witness testimony. Finally, this claim must not have been previously heard at trial or in a post-conviction hearing.

These conditions disqualify many applicants early in the process. 28 percent of rejected cases lacked new evidence, while another 20 percent had no way to prove their claims. 21 percent of rejected cases did not claim complete factual innocence of the crimes. In 9 percent of rejections, the evidence itself was deemed unreliable. North Carolina law requires the commission to prioritize investigations of trial cases over plea cases. Beyond that, investigators have broad discretion to choose which cases to focus on. Everyone on the nine-person staff that supports the commission’s work has multiple cases assigned to them.

After the case has been thoroughly investigated, the agency may choose to hold a formal inquiry at which the claimant can testify and present evidence. Investigators then present their case to the commission itself at a hearing. The full commission consists of eight members, including a prosecutor, a criminal-defense attorney, a sheriff, a superior court judge, a victims’ rights advocate, a member of the public, and two discretionary appointments. The commission evaluates the case and votes to submit it to a special tribunal for review. If the three-judge panel unanimously finds that the evidence for actual innocence is clear and convincing, the claimant is exonerated and immediately released.