A grand jury investigation begun by Special Counsel Robert Mueller III is “continuing robustly,” a U.S. Justice Department prosecutor said Wednesday in arguing for continued secrecy around a case involving a foreign government-owned corporation that has resisted a subpoena.

Justice Department attorney David Goodhand confirmed that the grand jury’s investigation was ongoing in response to a question from Chief Judge Beryl Howell, who heard arguments in Washington about whether to reveal the identity of the foreign-owned corporation.