James Comey speaks onstage at 92NY on May 30, 2023 in New York City. (Dia Dipasupil/Getty Images)(NEW YORK) — A Columbia law professor who is a friend and adviser to former FBI Director James Comey was subpoenaed last week by federal prosecutors in connection with a criminal probe into whether Comey allegedly lied in testimony before Congress, sources familiar with the matter told ABC News. Richman met with federal prosecutors in the Eastern District of Virginia on Tuesday, sources familiar with the matter said. The subpoena to Richman, according to sources, stems from an investigation into testimony Comey made before Congress in September 2020 about the investigation into Russian interference in the 2016 election. An attorney for Richman and an attorney for Comey did not immediately respond to a request for comment from ABC News.