The U.S. Department of Justice declared 17 Capitol riot cases at a “standstill” Monday after federal prosecutors said they haven’t been able to contact John Pierce, the prominent conservative attorney involved in those cases, and have heard conflicting information about his absence, including that he may be gravely ill with COVID-19.

Prosecutors filed five-page notices in the cases Pierce is listed as counsel informing judges about his reported illness and declaring that they will no longer deal with Pierce’s associate, Ryan Marshall, who is not a licensed attorney and has been appearing in court in place of Pierce. Continuing to communicate with Marshall could run afoul of ethics rules that require a licensed attorney to supervise unlicensed staff, prosecutors said.