A year after the breach, falsehoods about Jan. 6 persist. Here’s a fact-check.

A mountain of evidence shows that the rioters were supporters of Mr. Trump, but that has not stopped the cascade of specious claims seeking to pin responsibility on others.

A false theory blaming agitators affiliated with antifa, a loose collection of antifascist activists, began to spread on social media before the riot had even ended. Republican members of Congress and Fox News personalities quickly repeated versions of the claim.

Two days after the Capitol was breached, the F.B.I. said there was no evidence that supporters of antifa had participated in the riot. None of the more than 729 people charged in connection to the riot so far have any connection to antifa, according to an NPR database of arrest records. Some took umbrage that antifa had received credit at all.

“Don’t you dare try to tell me that people are blaming this on antifa and BLM,” one participant wrote on his Facebook page, according to charging documents. “We proudly take responsibility for storming the Castle.”

Still, belief in the false theory persisted. More than 70 percent of Republicans surveyed in a Yahoo News/YouGov poll in May and more than half in a P.R.R.I. poll in September maintained that left-wing protesters were culpable for the attack.

Mr. Trump has continued to push the theory, telling the Fox News host Sean Hannity in November that “bad people that were not patriots at all,” including supporters of antifa, “led a lot of people astray” at the Capitol.

Republican lawmakers and other supporters of Mr. Trump have falsely claimed that Ms. Pelosi ignored pleas from Capitol Police for more resources that day and “denied the ability to bring the National Guard” to the Capitol.

These claims, which have circulated widely on social media for months, are not true.

There is no evidence that Ms. Pelosi’s office rejected a request to deploy the National Guard, or even played a role in delays over approval. And as speaker, Ms. Pelosi does not directly oversee security operations at the Capitol.

Many have criticized the treatment of those arrested in connection with the Jan. 6 attack, with some lawmakers and right-wing activists describing the arrestees as “political prisoners” or complaining of an “unequal administration of justice.” More than a third of Republicans said in a Pew poll in September that the penalties the Capitol rioters were facing were too severe.

Local officials have complained for years about the conditions at the District of Columbia jails, where dozens of the rioters have been detained in recent months, and some have raised concerns about dealing with threats from guards, standing sewage, and scant food and water.

Whether the punishments doled out so far against the rioters have been overly harsh is a matter of opinion. But most of the rioters who were arrested were later released while awaiting trial. Those detained faced serious charges like assaulting police officers; they were not singled out for their political beliefs. Out of the more than 700 arrested, only about 71 people have been sentenced so far, 30 of whom have received prison time with a median sentence of 45 days, according to a Politico analysis.

Others have speculated, without evidence, that federal agents had organized the riot to entrap supporters of Mr. Trump.

F.B.I. agents and informants have been cited in charging documents as “a confidential source,” “a confidential human source” or simply “an informant,” or those “acting in an undercover capacity.” According to the theory, those listed as “unindicted co-conspirators” in the documents were also undercover F.B.I. agents or informants.

The New York Times reported in September that two F.B.I. informants with ties to the far-right group the Proud Boys had participated in the events on Jan. 6. But that does not amount to evidence that the F.B.I. had orchestrated the attack to ensnare Trump supporters. Moreover, records show one of the informants traveled to Washington of his own volition, not at the behest of his handler.

On Twitter, Candace Owens, the right-wing news personality, has speculated, with no evidence, that “undercover FEDS” planted explosive devices at the Republican National Committee and the Democratic National Committee on the day before the riot. Mr. Trump himself has toyed with the theory, noting in a December interview that the case remained unresolved and was suspicious.

Officials have yet to identify, at least publicly, or arrest the person who placed the devices. But that does not prove purposeful concealment or the F.B.I.’s involvement. The agency is offering a $100,000 reward for any information that could help identify the suspect. Moreover, the F.B.I. has posted hundreds of photos and videos of individuals involved in the riot that they have yet to identify.

The riot at the Capitol resulted in injuries to about 150 federal and local police officers as well as $1.5 million in damages to the Capitol. Yet despite graphic videos depicting assaults and destruction, a chorus of prominent conservative voices have insisted that the events were largely nonviolent, akin to a “peaceful protest” or “normal tourist visit.” A year later, roughly a third of Republicans believe that the attack on the Capitol was mainly peaceful, according to several recent polls.

Mr. Trump has repeatedly, and misleadingly, compared violence at the Capitol riot to that of the racial justice protests of 2020. In several interviews on Fox News last year, he said “there were no guns whatsoever” and only one fatality during the riot compared with multiple fatalities, “plenty of guns” and “no repercussions” during Black Lives Matter protests.

Those claims are false. At least three Jan. 6 rioters face gun charges, including a Maryland resident who took a gun into the Capitol. According to the Justice Department, over 75 defendants have been charged with entering a restricted area with a dangerous or deadly weapon. A bipartisan Senate report tied seven fatalities to the assault. On the day of the attack, two protesters died of heart attacks, one of an accidental overdose, and one — Ashli Babbitt — was shot while trying to enter the Speaker’s Lobby of the Capitol through a broken glass door. A Capitol Police officer died of multiple strokes a day after the attack, and two others killed themselves in the days afterward. (Two other officers died by suicide six months later.)

Several lawmakers have echoed Mr. Trump’s comparisons between the racial justice protests of 2020 and the Jan. 6 riot.

But according to experts and data, violence was more prevalent during the Capitol breach, and the Jan. 6 rioters were more organized and intended to injure lawmakers and law enforcement at a higher rate.

“One of the things we’ve learned from the Capitol arrests is that there was a small but sizable core of folks who planned what I would describe as lethal violence or attempts at lethal violence. There was no such intent in the Floyd protests,” said Michael Loadenthal, the executive director of the Prosecution Project, which tallies federal cases involving political violence.

About 15 million to 26 million people participated in Black Lives Matter protests across the United States in the summer of 2020, and the vast majority of them were peaceful. More than 17,000 people were arrested in connection to the racial justice protests, according to a tally by The Washington Post. Out of some 2,600 arrests with details about the charge or protester, 582, or about 22 percent, were charged with crimes related to violence or the threat of violence. In other words, 1 in about 4,400 committed a violent crime, assuming the same crime rate across the entire arrestee population.

In comparison, crowd experts and officials have estimated that up to 10,000 people entered the Capitol grounds. Out of the more than 729 arrested so far, 176, or about a quarter, have been charged with crimes related to violence. In other words, at least 1 in 56 committed a violent crime.