Two prosecutors have left special counsel Robert Mueller’s office for unexplained reasons. The Justice Department confirmed to CNN that Ryan Dickey and Brian Richardson—relatively junior members of Mueller’s team—are no longer working for the special counsel’s office. Both have reportedly been working on cases that Mueller opened as part of his investigation into Russian interference and alleged coordination with the Trump campaign in the 2016 presidential election. Peter Carr, a spokesman for the special counsel, declined to explain why they left—but said that neither quit due to political allegations, bias, or any other wrongdoing. The special counsel’s office now has 15 lawyers at work under Mueller.