Attorneys for longtime Trump confidant Roger Stone asked a federal judge Thursday to postpone his scheduled Feb. 6 sentencing by at least one month, saying he needs more time to collect financial and other records needed for a sentencing advisory report.

Stone, 67, was convicted by a federal jury in Washington last month of one count of tampering with a witness and six counts of lying to Congress about his efforts to learn of hacked Democratic emails during the 2016 U.S. presidential election.

Stone faces a maximum 50 years in prison for the charges, although a first offender would face far less time under federal sentencing guidelines. Stone was charged as part of special counsel Robert S. Mueller III’s investigation into Russian election interference.

A presentencing investigation into whether a person’s background may warrant a harsher or more lenient punishment is a necessary step in the federal sentencing process. U.S. District Judge Amy Berman Jackson had ordered the report to be completed by Jan. 9, but Stone’s attorneys said they are unable to meet probation officials’ deadlines.

“Despite the continual and diligent work of Mr. Stone, the process, however, is not yet complete, particularly financial records and information necessary to prepare Mr. Stone’s financial disclosure statement, which are extensive and not all immediately available,” Stone’s attorneys wrote.

They asked to postpone sentencing to after March 9 to allow time for Stone and probation officials to finish the report. They also said they needed more time to account for “the upcoming holiday period, and other commitments of the subject matter professionals and counsel.”

Federal prosecutors oppose the delay, Stone’s attorneys said, and will file their own reasons for Jackson to weigh before ruling.

Stone, who is free pending sentencing, was convicted of charges resulting from his September 2017 testimony to the House Intelligence Committee, which was investigating Russian interference in the 2016 election and the Kremlin’s efforts to damage Donald Trump’s Democratic opponent, Hillary Clinton.

Stone’s indictment was the last brought by Mueller, which charged him of lying to conceal the Trump campaign’s interest in his efforts to learn about computer files made public by the anti-secrecy group WikiLeaks after the government alleges they were hacked by Russia.