Attorney General Merrick Garland on Friday appointed David Weiss, the Delaware federal prosecutor who has led the investigation into Hunter Biden, as a special counsel overseeing the investigation.

The move comes as a pending plea deal involving Biden appears to be unwinding.

Garland said he made the decision in the politically explosive case after Weiss asked for the appointment.

“On Tuesday of this week, Mr. Weiss advised me that in his judgment, his investigation had reached a stage at which he should continue his work as a special counsel, and he asked to be so appointed,” Garland said in a statement to the press on Friday.

“Upon considering his request, as well as the extraordinary circumstances relating to this matter, I have concluded that it is in the public interest to appoint him as special counsel.”

Republicans have launched a probe into the investigation of Biden following claims from two IRS whistleblowers that Weiss was blocked from seeking special counsel status – a claim Weiss and DOJ have consistently denied.

Meanwhile, in a court filing just moments after Garland’s announcement, the Justice Department indicated the parties had reached an impasse on still reaching a plea agreement.

“The Government now believes that the case will not resolve short of a trial,” prosecutors wrote in court filings on Friday.