Officials say the probe is one of the largest and most resource-intensive investigations in American history. More than 700 people have been charged already.

Transcript

A MARTINEZ, HOST:

It's been one year since a mob of Trump supporters ransacked the U.S. Capitol. There are several efforts to bring those responsible to account. A House Select Committee has been interviewing witnesses and issuing subpoenas. Several lawsuits are seeking damages from former President Trump and others in connection with the events of January 6, and the Justice Department is prosecuting those who bear criminal responsibility. NPR justice correspondent Ryan Lucas has been closely following that department's efforts. Ryan, bring us up to date. What is the status of the Justice Department's investigation?

RYAN LUCAS, BYLINE: Well, look, this is one of the largest, if not the largest, investigation in U.S. history. This thing spans the entire country. More than 725 people have been arrested so far, and that number keeps going up. As of December 30, around 165 Capitol riot defendants have pleaded guilty, and that number ticks up every week as well. Approximately 70 people have been sentenced so far - more than half to probation and the rest to jail time. And remember, the crime scene here is the United States Capitol. The images and sounds from that day are seared into our collective memory...

(SOUNDBITE OF PEOPLE RIOTING)

LUCAS: ...And of that mob swarming up the Capitol steps, beating police officers with everything from fists to flagpoles - rioters, some of them waving blue or red Trump 2020 flags, careening through the ornate hallways of the U.S. Capitol.

As soon as cleaning crews returned to pick up the pieces, federal investigators went to work to try to piece together what happened and track down those involved. Here's FBI Director Christopher Wray testifying before Congress in March.

(SOUNDBITE OF ARCHIVED RECORDING)

CHRISTOPHER WRAY: We're chasing down leads. We're reviewing evidence, combing through digital media to identify, investigate and arrest anyone who broke the law that day.

LUCAS: In the past year, the FBI and the public have learned a lot about who the rioters were and what motivated them, and they fall into three general categories. The first are the so-called MAGA tourists. These are Trump supporters who entered the Capitol but didn't engage in violence or destroy property.

Take Frank Scavo, a former school board president from Old Forge, Penn. According to court documents, Scavo organized several buses to travel to Washington, D.C., for then-President Trump's Stop the Steal rally near the White House on January 6. The day after the riot, Scavo spoke to local television station WBRE WYOU.

(SOUNDBITE OF ARCHIVED RECORDING)

FRANK SCAVO: I just gave it some direction to go down to Washington and show that we are here and we're watching. The people that went crazy - you know, that's free will. I can't control it. I'm not responsible for that.

LUCAS: Scavo also denied that he had entered the Capitol. That turned out not to be true. Videos that he took on his own cellphone show him in a mass of rioters outside the doors to the Capitol.

(SOUNDBITE OF ARCHIVED RECORDING)

UNIDENTIFIED RIOTERS: Heave. Heave. Heave.

LUCAS: At one point, Scavo turns the camera on himself and says...

(SOUNDBITE OF ARCHIVED RECORDING)

SCAVO: Here we go.

LUCAS: Once inside, he sharks through the halls of the Capitol with other rioters and continues to film on his cellphone.

(SOUNDBITE OF ARCHIVED RECORDING)

SCAVO: Yeah. Well, I always knew it would come to this day.

LUCAS: Ultimately, Scavo surrendered to the FBI. He pleaded guilty to a single misdemeanor count of parading, demonstrating or picketing in a Capitol building. At a sentencing hearing in late November, Scavo said he regretted his actions, but he also claimed he just kind of got swept into the building along with the crowd. Judge Royce Lamberth seemed skeptical. Without folks like Scavo, he said, January 6 would never have happened. And he sentenced Scavo to 60 days in prison.

Among the January 6 defendants who weren't violent, Scavo's sentence is an outlier. Most non-violent defendants have received probation. Of those accused of violence, a half-dozen or so have pleaded guilty and been sentenced to jail time so far. Most, however, are still fighting the charges. One of them is Daniel Rodriguez.

According to court papers, Rodriguez was involved in one of the more notorious attacks on law enforcement on January 6 - the assault of D.C. Police Officer Michael Fanone. When Fanone testified before Congress, he said he feared for his life that day after he was pulled into the mob.

(SOUNDBITE OF ARCHIVED RECORDING)

MICHAEL FANONE: I was electrocuted again and again and again with a Taser. I'm sure I was screaming, but I don't think I could even hear my own voice.

LUCAS: The man accused of tasing Fanone is Rodriguez. And in this interview with FBI agents after his arrest, he had this to say.

(SOUNDBITE OF ARCHIVED RECORDING)

DANIEL RODRIGUEZ: What do you want me to tell you, that I tased him? Yes.

UNIDENTIFIED FBI AGENT: Explain...

RODRIGUEZ: Am I a [expletive] piece of [expletive]? Yes.

UNIDENTIFIED FBI AGENT: Why did you tase him?

RODRIGUEZ: I don't know. I'm a piece of [expletive]. (Crying) I'm sorry. I don't know. He's a human being with children.

LUCAS: According to court documents, Rodriguez entered the Capitol on January 6 through a broken window. Once inside, videos show him trying to smash another window with a flagpole. In his FBI interview, he tells agents that he and others came to D.C. because Trump needed their help. He says that when storming the Capitol, he thought the rioters were going to save the country.

(SOUNDBITE OF ARCHIVED RECORDING)

RODRIGUEZ: I'm so sorry. I didn't know that we were doing the wrong thing. I thought we were doing the [expletive] right thing. I thought we were going to be - I'm so stupid. I thought I was going to be awesome. (Crying) I thought I was the good guy.

LUCAS: The video of Rodriguez's questioning has been made public as part of his court case. For now, Rodriguez remains in federal custody pending trial.

The third group of defendants is the smallest but also perhaps the most concerning. These are people accused of having ties to extremist groups such as the Oath Keepers or the Proud Boys. Take, for example, Joseph Biggs, a self-proclaimed Proud Boys member. Here he is being interviewed on the "Drinkin' Bros" podcast in 2019.

(SOUNDBITE OF PODCAST, "DRINKIN' BROS")

JOSEPH BIGGS: My IP on my phone, my computers, my internet at the house - I've got to hide all the [expletive] because I constantly have people looking for me, too. I got a bunch of those psychotic left nut jobs out there, which - I kind of wish they would knock on my door. I think that would be amazing.

LUCAS: Prosecutors say that on January 6, Biggs and his co-defendants directed a mob of Proud Boys towards and ultimately into the Capitol. Videos from that day show Biggs - dressed in a gray flannel shirt, stocking cap and glasses - addressing a gaggle of Proud Boys outside the Capitol.

(SOUNDBITE OF ARCHIVED RECORDING)

BIGGS: If you're on the outside, making sure you're looking on the outside of the perimeter - no one's sneaking up on us.

LUCAS: Later in the day, videos show Biggs at the front lines as the mob pulls down metal fencing and surges up the steps past police.

(SOUNDBITE OF ARCHIVED RECORDING)

BIGGS: (Chanting) We the people. We the people.

LUCAS: Biggs ultimately made his way inside the Capitol. As he and other rioters rushed through the halls, someone pointed a camera at him and asked...

(SOUNDBITE OF ARCHIVED RECORDING)

UNIDENTIFIED PERSON: Biggs, what do you got to say?

LUCAS: Biggs pulls down his mask and responds, this is awesome. Biggs has been indicted along with three other alleged Proud Boy leaders on charges of conspiracy, obstruction and other offenses. He has pleaded not guilty.

MARTINEZ: Ryan, I still can't believe what I saw on TV a year ago. And it's still tough to believe and process what you just played just moments ago. But listening to some of those defendants, Ryan, it's clear that some of them say they were motivated by President Trump. As of today, is he facing any legal repercussions over what happened on January 6?

LUCAS: Well, he's facing several civil lawsuits. But for all the progress that the Justice Department has made over the past year in this investigation, it's facing criticism that Trump and those in his inner circle, so far at least, have not publicly faced legal scrutiny from the department. We do know, however, that the House Committee investigating January 6 is certainly examining that angle.

But, look, there's a lot of digging still to be done by the Justice Department in this investigation. Prosecutors say that up to 2,500 people stormed the Capitol, so there's still a long way to go to hold all of them accountable. And, of course, there's still the mystery behind the two pipe bombs that were planted near the Capitol on the eve of the riot. Those didn't go off, of course, but investigators, a year later, are still searching for who was behind those.

MARTINEZ: NPR justice correspondent Ryan Lucas. Ryan, thanks a lot.

LUCAS: Thank you. Transcript provided by NPR, Copyright NPR.