Steve Bannon should be sentenced to six months in prison and a $200,000 fine for “his sustained, bad-faith contempt of Congress”, the justice department said in a legal filing on Monday.

Bannon, the former Donald Trump White House strategist, was found guilty on two counts of criminal contempt of Congress in July for ignoring a subpoena from the US House committee investigating the January 6 attack.

Bannon faces up to a year in prison on each count on which he was found guilty. The punishment proposed Monday is at the “top end” of government sentencing guidelines and was needed because Bannon “consistently acted in bad faith and with the purpose of frustrating the committee’s work”, US justice department prosecutors wrote.

They said Bannon had refused to cooperate with the committee in any way, except for instances in which he attempted a quid pro quo of exchanging information for dismissal of his criminal case.

Bannon’s “contempt of Congress was absolute and undertaken in bad faith”, prosecutors added in the filing, which was submitted ahead of the ex-Trump adviser’s scheduled sentencing Friday. “To date, he remains in default: more than one year after accepting service of the committee’s subpoena, [Bannon] has not produced a single document or answered a single deposition question – nor has he endeavored to do so, except as part of a duplicitous quid pro quo.”

Earlier this month, the FBI interviewed Timothy Heaphy, a senior investigator on the January 6 committee. Heaphy told an FBI agent that just before Bannon’s trial this summer, Bannon’s lawyer Evan Corcoran contacted him. Corcoran wanted to see if the committee would be willing to support a dismissal of Bannon’s charges in exchange for testimony, according to a document filed in court. Heaphy declined, since the committee was not involved in criminal charges and said he had not heard from Bannon’s lawyer since.

The filing details numerous instances over the last several months in which Bannon dangled the prospect of cooperation with the committee in exchange for delaying and dismissing criminal charges against him.

“His noncompliance has been complete and unremitting,” the justice department wrote. “And his effort to exact a quid pro quo with the committee to persuade the Department of Justice to delay trial and dismiss the charges against him should leave no doubt that his contempt was deliberate and continues to this day.”

Prosecutors’ filing also said Bannon had refused to provide financial information to the probation office as part of its effort to evaluate what kind of fine he could pay. Bannon has said he would pay the maximum punishment instead.

“Rather than disclose his financial records, a requirement with which every other defendant found guilty of a crime is expected to comply, [Bannon] informed [sentencing investigators] that he would prefer instead to pay the maximum fine,” the justice department argued. “So be it.”

Prosecutors also pointed to Bannon’s comments on his podcast in which he used violent and intimidating rhetoric against members of the committee. “We’re going medieval on these people, we’re going to savage our enemies,” he said in one July appearance.

“Through his public platforms, [Bannon] has used hyperbolic and sometimes violent rhetoric to disparage the committee’s investigation, personally attack the committee’s members, and ridicule the criminal justice system,” the filing said. “The … statements prove that his contempt was not aimed at protecting executive privilege or the constitution, rather it was aimed at undermining the committee’s efforts to investigate an historic attack on government.”

The January 6 committee, which has relied heavily on testimony from former Trump administration official, held what was likely its final public hearing last week. It ended the meeting by voting 9-0 to subpoena Trump.

The department is also pursuing criminal charges against Peter Navarro, another Trump White House adviser, who has refused to comply with the committee’s subpoena.