WASHINGTON (NewsNation Now) — The U.S. Justice Department has opened criminal investigations of more than 170 individuals on their involvement in the riot at the U.S. Capitol by President Donald Trump’s supporters, and investigators are working toward charging people with assault and seditious conspiracy, the top federal prosecutor in Washington, D.C. said on Tuesday.

“I think the scope and scale of this investigation and these cases are really unprecedented, not only in FBI history, but probably DOJ history,” Acting U.S. Attorney Michael Sherwin said in a press briefing on Tuesday.

Sherwin said 70 criminal cases have been filed to date. While many of them involve people whose photos went viral on social media, such as one of a man pictured sitting at the desk of a staffer of House Speaker Nancy Pelosi, he said more serious charges are coming and a grand jury has been reviewing the cases.

“We’re looking at significant felony cases tied to sedition and conspiracy,” Sherwin said, noting his office has launched a strike force whose marching orders are to build criminal cases around such charges.

He added that other strike forces have been formed to focus on assaults on law enforcement and members of the media. 

Officials also confirmed the pipe bombs found at the Democratic National Committee and Republican National Committee headquarters were real devices with “explosive igniters” and times.

The FBI recently warned of plans for armed protests at all 50 state capitals and in Washington in the days leading up to President-elect Joe Biden’s inauguration. An internal FBI bulletin warned that, as of Sunday, the nationwide protests may start later this week and extend through Jan. 20, according to two law enforcement officials who read details of the memo to The Associated Press. 

The chief of the National Guard Bureau said Monday that the Guard is also looking at any issues across the country, as state capitols have begun to step up security.

Five people died in the violence last week, including a Capitol police officer. Two explosive devices were found, but they did not go off.

Meanwhile, federal officials continue to announce arrests of individuals involved in the Capitol attack.

On Tuesday, the FBI announced the arrest of a New York City judge’s son. Aaron Mostofsky was picked up at his brother’s home in Brooklyn, about a week after he was seen inside the Capitol wearing a fur costume and a police vest he is accused of stealing during the mayhem.

Court papers show how investigators are combing through internet communications to identify alleged offenders like Mostofsky, who referred to himself as a “caveman” eager to protest the presidential election results.

Mostofsky, 34, is facing charges including felony theft of government property — a police bulletproof vest worth $1,905 and a riot shield valued at $265.