The federal judge who must decide whether Paul Manafort lied to investigators after pledging to cooperate with Special Counsel Robert Mueller’s Russia probe began a hearing Monday in a sealed courtroom to discuss secret evidence gathered by the government.

A court officer cleared the Washington courtroom before U.S. District Judge Amy Berman Jackson took the bench. Mueller’s arguments to support his claims that President Donald Trump’s former campaign chairman breached a plea deal were heavily redacted in publicly filed documents.

Thick loose-leaf binders could be seen near lawyers for the government and Manafort before the courtroom was sealed. Manafort, who is being held in jail following his conviction for fraud and other crimes, wasn’t in the courtroom when reporters were ejected.

Jackson, who held a brief hearing on the matter last month, is set to sentence Manafort on March 5 for two conspiracy counts. Her decision on the alleged deal breach could influence how harshly she sentences him.