WASHINGTON (Reuters) — The U.S. Justice Department is considering whether to charge members of far-right groups involved in the deadly Jan. 6 storming of the Capitol under a federal law usually used against organized crime, according to two law enforcement sources.

The Racketeer Influenced and Corrupt Organizations Act, known as RICO, enables prosecutors to combat certain ongoing racketeering crimes such as murder, kidnapping, bribery and money laundering. The 1970 statute provides for hefty criminal penalties including up to 20 years in prison and seizure of assets obtained illegally through a criminal enterprise.

The sources, a current law enforcement official and a former official who recently left the federal government, said using the RICO statute to charge people involved in the Capitol violence is being debated within the Justice Department, with no final decision made. The sources spoke on condition of anonymity.

The siege by supporters of former President Donald Trump left five dead including a police officer. It is not yet clear if cases arising from it meet “statutory elements” necessary for a RICO charge, the former federal official said.

“This is something that is being mulled over in the halls of DOJ,” the official added, using the department’s initials.

President Joe Biden’s administration has warned that domestic extremism is a growing threat following the Capitol rampage, a sharp departure from the way Trump regarded extremist groups such as the Proud Boys and Oath Keepers. In a September pre-election debate with Biden, Trump told the Proud Boys to “stand back and stand by.”

Justice Department spokeswoman Kristina Mastropasqua declined to comment about the potential use of the RICO statute beyond pointing to prior statements by the senior federal prosecutor for the District of Columbia, Michael Sherwin, that he would charge people based on what the evidence showed.

Sherwin has said a wide range of criminal charges are being contemplated, including trespassing, assault and seditious conspiracy.

The RICO law was crafted to help prosecutors convict top Mafia leaders who ordered others to commit crimes. RICO cases are complex, often take years to develop, and require approval from Justice Department leadership.

“RICO was designed to address the Godfather – the person who doesn’t get their hands bloody,” said Jeffrey Grell, an attorney who specializes in RICO law. “You would really only use RICO to go after the kingpins or the leaders.”

Prosecutors have used it against other violent groups, such as one led by Omar Abdel Rahman, known as the “Blind Sheikh,” who was convicted of plotting to bomb the United Nations and George Washington Bridge in New York.

More than 170 people have been charged in connection with the Capitol attack that interrupted the formal congressional certification of Biden’s election victory over Trump and sent lawmakers into hiding for their own safety.

Democratic Senator Richard Durbin (D-IL), tapped to become chairman of the Senate Judiciary Committee, is advocating possible RICO charges. A Durbin spokesperson said, “There are multiple statutes currently available for federal prosecutors to use to hold the perpetrators behind the Jan. 6 attack accountable, including RICO, and prosecutors should appropriately evaluate potential charges.”

‘RACKETEERING ACTIVITY’

Obstructing an official government proceeding, the charge some Oath Keepers and Proud Boy members are currently facing, is considered a “racketeering activity.”

Prosecutors in a RICO case would need to show that the far-right groups qualify as a “criminal enterprise” and that members of the enterprise engaged in a pattern of two or more related crimes beyond the Capitol riots.

That could mean looking at whether these groups engaged in similar actions at other events, such as the violent 2017 “Unite the Right” rally in Charlottesville, Virginia, or other violent activities such as storming state capitols.

“Whatever theory they’re pursuing requires looking at the group and kind of zooming out so they can capture a pattern of racketeering activity more than just what happened on that day,” said Kamal Ghali, an Atlanta attorney and former federal prosecutor.

In a RICO case, prosecutors must show a pattern of related racketeering crimes and a threat of continuing criminal conduct.

A Washington grand jury last month indicted three Oath Keepers members on charges that they conspired to forcibly storm the Capitol. Two Proud Boys members were indicted on charges they conspired with others to obstruct law enforcement from protecting the Capitol.

In a sworn statement, an FBI agent said Thomas Caldwell, a defendant in the Oath Keepers indictment, sent messages after the attack urging others to keep fighting.

“We need to do this at the local level,” Caldwell was quoted by the FBI as saying. “Lets storm the capitol in Ohio. Tell me when!”

Federal prosecutors in Ohio convinced a judge to detain Caldwell’s co-defendant Donovan Crowl by citing recent writings by the group’s leader Elmer Stewart Rhodes. After the riots, Rhodes urged members to begin organizing in “friendly red” counties – jurisdictions that lean Republican – saying the Biden administration represents an “illegitimate regime.”

The three Oath Keepers have not yet entered pleas, though Caldwell has previously said in court that “every single charge is false.” Rhodes did not respond to requests for comment.