The federal judge overseeing Paul Manafort’s criminal case in the District of Columbia said Friday she has not yet made a determination as to whether the former Trump campaign chairman lied to federal prosecutors in breach of his plea agreement.

Judge Amy Berman Jackson, an Obama appointee on the federal district court in Washington, D.C., said her decision will be fundamental to the eventual sentence she hands down.

{mosads}Jackson scheduled a hearing for 10 a.m. on Feb. 4 to hear arguments in the dispute, but said the proceedings will be sealed.

“I know everyone in the courtroom who is here does not want that to be the case, but we will do our best to get as much of the transcript released as soon as possible,” she said.

Special counsel Robert Mueller has accused Manafort of breaching his plea deal and committing new crimes by lying to federal prosecutors about five different subject matters, including his contacts with the Trump administration officials and his interactions and meetings with Konstantin Kilimnik, a former business associate who is suspected of having ties to Russian intelligence, during the 2016 presidential campaign.

Jackson signaled on Friday that she has doubts about some of Mueller’s allegations.

She said that “while investigators shouldn’t have to pull teeth,” she may conclude that “not all instances rise to the level of actionable false statements.”

At the same time, she said she has serious concerns about other instances where Manafort advanced a version of events that were later shown to be false.

Manafort was in court Friday, walking slowly into the room with a cane. He was dressed in a business suit instead of his prison uniform. His wife Kathleen was also in attendance Friday.

Manafort’s appearance came just hours after former Trump campaign adviser Roger Stone was arrested on charges related to his alleged obstruction of investigations by the House Intelligence Committee and FBI into Russian interference in the election.

Stone was indicted by a federal grand jury on one count of obstructing a proceeding, five counts of giving false statements and one count of witness tampering.

The stepson of Jerome Corsi, an associate of Stone, appeared before Mueller’s grand jury on Thursday and was questioned about a computer that he and Corsi had discussed being “scrubbed,” The Associated Press reported.

Mueller has been sussing out whether Corsi and Stone had prior knowledge that WikiLeaks would release hacked Democratic emails before the 2016 election.

During Friday’s hearing, federal prosecutors told Jackson they don’t intend to bring old or new charges against Manafort but want to reserve their right to do so in the future.

Prosecutor Andrew Weissmann said old charges could come from the superseding indictment the government had originally agreed to dismiss as part of Manafort’s deal with prosecutors.

Weissmann said that as a result of the breach, the government no longer has to adhere to its prior promises and may bring new charges.

Manafort was previously convicted of eight counts of bank and tax fraud during a criminal trial held in Virginia. Sentencing in that case is scheduled for Feb. 8.

The parties indicated to Jackson that they would like to settle the dispute over whether Manafort breached his plea agreement before he is sentenced next month.

“I don’t know how hard it’s going to be to make up my mind at the end of the day,” Jackson said.

As part of the plea deal that allowed Manafort to avoid a second criminal trial in D.C., prosecutors agreed to dismiss all but two counts of conspiracy, which together carry a maximum of 10 years in prison, and allow his sentence in D.C. to run concurrently with his sentence in Virginia. In exchange, Manafort agreed to fully cooperate with the special counsel’s investigation.

It’s now up to the court to decide whether he breached that deal and if so what effect it will have on his sentence.

Jackson said she has to decide where Manafort’s sentence should fall in the sentencing guidelines, whether to run the sentence for each charge consecutively or concurrently and whether to run the D.C. sentence consecutively or concurrently with the sentence he receives in the Eastern District of Virginia.

Updated at 12:59 p.m.