The D.C. lobbyist who pleaded guilty in August in a prosecution linked to special prosecutor Robert Mueller’s Russia probe will have the details of his case remain under wraps, after prosecutors added yet another mystery filing to the docket.

D.C. federal prosecutors filed a joint status report in Patten’s case under seal Monday, after doing the same in a surprise New Year’s Eve move.

Patten pleaded guilty to failing to file as a foreign lobbyist in August, admitting in his plea that he took $50,000 from a Ukrainian oligarch and siphoned it into the Trump inaugural committee through a straw donor in exchange for tickets.

Contributing foreign money to inaugural committees is prohibited by federal campaign finance law.

Since Patten’s plea – and since the last filing in the case – the investigation into the Trump inauguration has heated up, with Manhattan federal prosecutors sending a subpoena to the committee last week amid allegations of pay-to-pay at the inaugural and questions about its accounting practices.

While Patten’s case is being prosecuted by the U.S. attorney’s office in Washington, D.C., and not by Mueller’s team, prosecutors from the Mueller investigation attended Patten’s plea hearing.

Patten has a link to former Trump campaign manager Paul Manafort. The Ukrainian oligarch who paid Patten the $50,000 for inaugural tickets was Serhiy Lyovochkin, who worked closely with Manafort during his time in Ukraine and who reportedly received polling data from him during the presidential campaign.

The lobbyist does not have a sentencing date set in his case yet. Prosecutors usually wait until an investigation is completed to sentence a cooperator.