The U.S. Attorney’s office in Washington, D.C., is reviewing 100 cases for potentially false and inaccurate tests by FBI analysts, The Washington Post reported ^[1] Sunday.

The cases date back to the mid-1970s, and the office has conducted a “preliminary review” of 78 of them, according to a report filed late Friday in D.C. Superior Court. The report stems from an internal investigation after the exoneration of Donald Gates, who was falsely imprisoned for the 1981 rape and slaying of a Georgetown University student. He was freed last December.

The review originally focused on 20 cases involving six FBI forensic analysts whose statements were called into question in a 1997 report by the department’s Office of Inspector General. In the course of the review, officials discovered an additional 100 cases on which the analysts worked.

Patricia Riley, a Special Counsel to Ronald Machen, U.S. Attorney for the District of Columbia, wrote that prosecutors had found no evidence of wrongful convictions, except in Gates’ case. Prosecutors have not submitted their findings in the remaining 22 cases.

“We intend to fully research the remainder of the cases to determine whether additional disclosures are required or appropriate,” Riley wrote in the report.

Sandra Levick, chief of the special litigation division for the Public Defenders Service, called the new report “troubling.”

“The government still does not know the number of people hurt by testimony from discredited FBI analysts, although it was given names beginning in 1997,” she said.