Thousands of criminal cases at the state and local level may have relied on exaggerated testimony or false forensic evidence to convict defendants of murder, rape and other felonies, reports the Washington Post. The forensic experts in these cases were trained by the same elite FBI team whose members gave misleading court testimony about hair matches and later taught the local examiners to follow the same suspect practices, according to interviews and documents. In July, the Justice Department announced a nationwide review of all cases handled by the FBI Laboratory’s hair and fibers unit before 2000 — at least 21,000 cases — to determine whether improper lab reports or testimony might have contributed to wrongful convictions.

But about three dozen FBI agents trained 600 to 1,000 state and local examiners to apply the same standards that have proved problematic. None of the local cases is included in the federal review. As a result, legal experts say, although the federal inquiry is laudable, the number of flawed cases at the state and local levels could be even higher, and those are going uncorrected. The FBI review was prompted by a Washington Post series about errors at the bureau’s renowned crime lab involving microscopic hair comparisons.