WASHINGTON (Reuters) - Former Trump campaign aide George Papadopoulos, who pleaded guilty in October to lying to FBI agents investigating possible collusion between President Donald Trump’s campaign and Russia, will be sentenced on Sept. 7, a judge ordered on Thursday.

Papadopoulos lied about contacts with people who claimed to have ties to top Russian officials, Special Counsel Robert Mueller said in court documents released with his guilty plea.

As part of a deal with prosecutors, Papadopoulos agreed to plead guilty to making a “materially false, fictitious and fraudulent statement” to FBI agents.

U.S. District Court Judge Randolph Moss set sentencing for Sept. 7 in a Washington court and ordered prosecutors to file their recommendation for punishment by Aug. 17.

Papadopoulos faces up to six months in jail and a fine of up to $9,500, but prosecutors said in the plea agreement that Papadopoulos was cooperating in the investigation, which could lessen his sentence.

Prosecutors said Papadopoulos told FBI agents he had been in contact with an unnamed foreign professor who claimed Russia had “dirt” on Democratic presidential candidate Hillary Clinton before he joined Trump’s campaign in March 2016. In fact, they said, Papadopoulos met with the professor after joining the campaign.

The prosecutors said Papadopoulos also lied to the FBI in saying that a meeting the professor arranged for him in London with an unidentified Russian woman with ties to senior Russian officials occurred before he joined the campaign.

Papadopoulos would be the second person sentenced in connection with Mueller’s probe. In April, Dutch lawyer Alex van der Zwaan was sentenced to 30 days in prison and fined $20,000 for lying to Mueller’s investigators.