A prominent conservative attorney representing more than a dozen defendants charged in the Jan. 6 riot at the U.S. Capitol is seriously ill and hasn’t appeared in court for more than a week, throwing some cases into disarray.

Attorney John Pierce has been sending an associate — who is not licensed to practice law — to appear before judges in his absence. Pierce’s illness has left some clients without counsel for the time being and is putting the cases at a “standstill,” prosecutors said in court papers this week.

On Thursday in one of Pierce’s cases in federal court in Washington, a judge said he would appoint an attorney who could advise the client in Pierce’s absence. That was after the associate at Pierce’s law firm, who is not licensed as a lawyer and faces criminal charges himself in another matter, was unable to say when Pierce might be able to return.

At a hearing later Thursday for Pierce’s newest client, Pierce’s associate was joined by a licensed attorney he said he had found to step in until Pierce returns.

Prosecutors repeatedly raised concerns this week that Pierce’s absence and the actions of his associate, Ryan Marshall, on the attorney’s behalf could cause problems in his cases, saying that Marshall had already done things he wasn’t allowed to do.

“Although Mr. Marshall has now appeared several times in Mr. Pierce’s place, he is not a licensed attorney and thus cannot appear in this Court, represent Mr. Pierce’s clients, or provide them with legal advice or services,” they wrote in one filing.

They also said it’s “unclear if and when Mr. Marshall will be able to obtain a bar license” since he is facing felony criminal charges including fraud in Pennsylvania state court.

Phone numbers for Pierce’s law firm did not appear to be working Thursday and it was not immediately clear how to reach Marshall.

Marshall told a judge Thursday in the case against a Kentucky man, Peter Schwartz, that Pierce remains hospitalized but is starting to feel better and expects to be released within a week. He didn’t elaborate on Pierce’s illness, but Marshall told a prosecutor last week that one of Pierce’s friends informed him that the attorney was sick with the coronavirus while another friend told him he was not, according to court documents.