Chief Justice John Roberts has stepped into a grand jury subpoena dispute that appears to involve special counsel Robert Mueller and an unknown company owned by a foreign country.

Roberts issued an order Sunday temporarily staying a contempt citation against the firm, as well as an escalating financial penalty a judge imposed for failing to comply with the subpoena.

The firm filed a stay petition at the Supreme Court on Saturday.

Roberts did not grant the motion, but issued what appears to be a temporary stay designed to allow the court to consider whether to wade into the fight.

He ordered the government to file a response by Dec. 31 at noon.

The identity of the firm and the foreign country at issue remain a mystery, but POLITICO first reported earlier this year that the dispute appeared to involve Mueller’s prosecutors.

A POLITICO reporter stationed in the D.C. Circuit Court of Appeals clerk’s office in October heard a person connected to the appeal request a copy of the special counsel’s latest filing in the case.

When the case was argued at the D.C. Circuit earlier this month, the courtroom was closed to the public.

Court personnel went to unusual lengths to preserve the secrecy, ordering journalists to leave the floor where lawyers were presenting their position.

The public docket in the appeal offers only modest detail about the dispute, containing no identification of the parties or their lawyers.

However, on Tuesday, the panel considering the appeal filed a three-page order revealing that the witness fighting the subpoena is a corporation owned by a foreign state.

The three-judge D.C. Circuit panel rejected the firm’s argument that its status as an extension of a foreign government makes it immune from grand jury subpoenas.

The judges also said they were not persuaded by the firm’s claims that complying with the subpoena would be violating the law in the company’s home country.

After the order was filed Tuesday, sealed filings continued in the appeals court in what appeared to be a bid to stay the D.C. Circuit’s ruling or appeal it further.

On Friday, the appeals court denied a motion from the company.

The precise nature of the motion was not disclosed.