Frederick Oberlander, a lawyer who has been disciplined over his use of sealed material, is still tangling with federal prosecutors over their ability to subpoena his files in a long-running criminal contempt investigation.

U.S. District Judge Brian Cogan of the Eastern District of New York referred Oberlander and his lawyer Richard E. Lerner to prosecutors more than seven years ago to consider charging them with criminal contempt for threatening to expose businessman Felix Sater’s cooperation with the government. The alleged threat came in the context of litigation involving the Bayrock Group, a real estate company where Sater worked.