Updated January 5, 2022 at 3:39 PM ET

Attorney General Merrick Garland pledged the Justice Department would hold to account people who broke the law in connection with the siege on the U.S. Capitol last Jan. 6, no matter their level or "whether they were present that day or were otherwise criminally responsible for the assault on democracy."

In a speech delivered Wednesday from the Justice Department's Great Hall, Garland addressed the federal response to what he called a "solemn anniversary" — the most significant assault on the seat of government since the War of 1812.

"We will follow the facts wherever they lead," Garland said. "The actions we have taken thus far will not be our last."

The investigation is now one of the biggest and most complicated in the department's long history. More than 700 people have been indicted for their roles in the insurrection, which injured 140 law enforcement officers. Five officers who reported for duty that day have since died.

In keeping with the Justice Department prohibition on discussing the specifics of ongoing investigations, the attorney general did not detail what steps, if any, the DOJ is taking to probe former President Donald Trump, his family members or others in his inner circle.

That has frustrated Rep. Ruben Gallego, D-Ariz., who told CNN recently that Garland had been "extremely weak."

"I think there should be a lot more of the organizers of Jan. 6 that should be arrested by now," Gallego added.

But Garland said that in complex probes, authorities frequently bring "less severe" cases first, as investigators "methodically collect and sift through more evidence." It could take a while for the Justice Department to develop a "full accounting," he added.

Authorities already have pored over 20,000 hours of video footage and have issued 5,000 subpoenas or search warrants. Many times, they've been aided by tips from ordinary citizens, whom Garland said were "our indispensable partners in this effort."

The attorney general sought to reach not only Justice Department employees, who appeared virtually on large screens set up in the stately hall because of COVID-19 precautions, but also a broader audience: the American people.

Garland decried violent threats to election workers, members of Congress, judges, airline personnel, health care workers and school administrators.

"These acts and threats of violence are not associated with any one set of partisan or ideological views," Garland said. "But they are permeating so many parts of our national life that they risk becoming normalized and routine if we do not stop them. That is dangerous for people's safety. And it is deeply dangerous for our democracy."

Sen. Dick Durbin, D-Ill., offered praise for the prosecutors and FBI agents who have labored to develop criminal cases against the Jan. 6 rioters. But in a written statement, Durbin added, "until those who unleashed the mob are also held accountable, the risk of future attacks on our democracy will continue to grow."

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