(The Hill) — Federal prosecutors on Monday added seditious conspiracy to the list of charges five Proud Boys leaders are facing over their alleged involvement in the Jan. 6 attack on the Capitol.

superseding federal grand jury indictment unsealed Monday marks the second time the Justice Department has brought the serious charge following the attack.

The five Proud Boys members, including the group’s national leader, Enrique Tarrio, had been charged over the past year with conspiracy to obstruct an official proceeding and various other counts.

Both of the types of conspiracy charges are punishable by up to 20 years in prison.

Prosecutors earlier this year charged members of the right-wing Oath Keepers militia with seditious conspiracy.

“Mr. Tarrio will have his day in court and we will vigorously represent our client through this process,” Tarrio’s lawyer, Nayib Hassan, said in an email. “Mr. Tarrio looks forward to being vindicated of these allegations.”

The new charges come as the Justice Department appears to be broadening the scope of its investigation into the attack. Former White House trade adviser Peter Navarro revealed last week that he had been subpoenaed by a federal grand jury for his communications with former President Trump.

The latest indictment doesn’t appear to add much new information to the case against the members of the Proud Boys group, who are scheduled to face a jury in August.

Seditious conspiracy involves planning to use violence to obstruct or overthrow the government. The Justice Department has historically only rarely brought such cases and have had mixed results in recent decades.

Prosecutors will now have to prove that the Proud Boys defendants conspired “to oppose the lawful transfer of presidential power by force.”

The new charges come two months after a sixth Proud Boys leader named as a defendant in earlier indictments, Charles Donohoe, pleaded guilty to conspiracy to obstruct an official proceeding and agreed to cooperate with the investigation and testify in court if necessary.

The five members now facing new charges have all pleaded not guilty and denied conspiring to prevent President Biden from taking office. Their lawyers have argued that the group’s efforts prior to Jan. 6 were to ensure that they could protect themselves in case they were attacked by leftist activists who they had clashed with at previous demonstrations around the country.

Tarrio was arrested in March and initially charged with conspiracy to obstruct an official proceeding and other counts, despite not being physically present at the Capitol on Jan. 6.

He had been arrested two days before the attack on Congress on unrelated charges and ordered to stay out of the district. But prosecutors allege he played a key role in preparing the group’s followers for an effort to prevent Congress from certifying President Biden’s 2020 victory over former President Trump.

“Tarrio nonetheless continued to direct and encourage the Proud Boys prior to and during the events of Jan. 6, 2021, and… he claimed credit for what had happened on social media and in an encrypted chat room during and after the attack,” the Justice Department said in March.

The other Proud Boys members had been charged last year.