Andrew Miller, who once worked as an aide to Trump ally Roger Stone, has been held in contempt of court for refusing to testify before a grand jury in special counsel Robert Mueller’s Russia investigation. Miller attempted to quash his subpoena, but a judge ruled this month that he would have to testify. Peter Flaherty, chairman of the National Legal and Policy Center, told The Washington Post that Miller refused to testify and is currently in Missouri. Mueller is investigating whether Russia interfered in the 2016 U.S. presidential election. Stone has appeared to suggest that he knew about hacked Democratic Party emails before they were posted by WikiLeaks, making him an object of Mueller’s scrutiny.