Washington — In the three years since members of a pro-Trump mob stormed the U.S. Capitol, attacked police and forced members of Congress from their legislative seats, investigators have embarked on one of the largest federal prosecutions in American history, securing convictions against individuals charged with a rare Civil War-era sedition count and accusing a former president of conspiring against the United States. 

In all, more than 1,200 defendants have been charged with crimes stemming from their alleged participation in the Jan. 6 2021 attack, according to a CBS News review of court records, with alleged crimes ranging from illegal picketing inside the Capitol to assaults on officers and destruction of government property. 

Over 700 of those defendants have pleaded guilty to crimes and accepted responsibility — a majority of them for misdemeanors that carry minimal prison time — and more than 100 have been convicted at jury or bench trials in Washington, D.C.

In the last year alone, federal judges have rendered the most severe sentences yet in the sprawling probe, sending Oath Keepers founder Stewart Rhodes to prison for 18 years and sentencing Proud Boys leader Erique Tarrio to 21 years, the longest prison term imposed so far. 

Washington, D.C.'s top federal prosecutor, who oversees the more than one thousand cases, U.S. Attorney Matthew Graves, said Thursday that the Oath Keepers and Proud Boys  — some of whom were convicted of seditious conspiracy in the last year — lit the flames that spread throughout the riot that day. 

According to investigators, 140 police officers were assaulted at the Capitol. Graves said the attack was likely the largest single event of assault on law enforcement in U.S. history, and he urged the public to assist prosecutors in working to find the more than 80 allegedly violent offenders who remain unidentified. 

Notably, since the attack, federal investigators have yet to locate an individual that they say planted potentially viable pipe bombs outside both the Democratic and Republican national party headquarters in the nation's capital on Jan. 5, 2021. 

The FBI is offering a $500,000 reward for information that could lead to the arrest of the alleged perpetrator. 

The last year has not been a complete success for federal prosecutors — they received mixed verdicts in the high-profile Proud Boys and Oath Keepers trials and a former Broadway-turned Jan. 6 defendant was acquitted by a judge of the two charges that remained after prosecutors agreed to drop other remaining counts. 

Months later, the validity of one of the more serious felony charges filed against numerous defendants — obstruction of an official proceeding — was thrown into doubt as the Supreme Court agreed to consider its constitutionality. 

The Justice Department has charged more than 327 defendants under this statute, which carries a maximum of 20 years in prison, and more than 50 have pleaded guilty to the count, according to a CBS News review of court documents and proceedings. 

Requests for the Supreme Court to weigh in on the obstruction statute arose from three criminal prosecutions of defendants charged for their alleged participation in the assault on the Capitol. The Justice Department had urged the Supreme Court to turn away the trio of cases, arguing in part that it was too early for the justices to intervene. 

Since the Supreme Court opted last month to take up a case about the law's application in Jan. 6 cases, numerous defendants — including an affiliate of the Oath Keepers — have successfully petitioned courts to delay their sentencing pending the litigation, and judges have warned of potential backlogs and delays should the justices declare the obstruction statute invalid. 

Former President Donald Trump was also charged with obstructing an official proceeding and three other counts stemming from his alleged efforts to resist the peaceful transfer of power after the 2020 presidential election. He pleaded not guilty to the charges and has mounted an attempt to dismiss the case based on presidential immunity, which will be considered by a federal appeals court in the nation's capital on Tuesday.

Special counsel Jack Smith, who sought the indictment against the former president, did not directly charge Trump with facilitating or promoting the Jan. 6 assault on the Capitol. But in court filings late last year, the special counsel revealed he could introduce evidence at trial demonstrating that the events of Jan. 6 were "exactly what [Trump] intended" to happen. 

Smith's team honed in on Trump's comments in support of Tarrio and pointed to a September 2023 interview in which Trump said of Tarrio that "he and other people have been treated horribly." The Jan. 6-related evidence that prosecutors plan to introduce at Trump's trial — including Trump's past mention of possibly pardoning defendants should he be reelected — "shows that these individuals acted as [Trump] directed them to act," the special counsel wrote in court documents. 

The trial is currently slated to begin in March, but could be delayed as the appeal moves forward. 

Throughout the hundreds of sentencings for Jan. 6 defendants in the three years since the attack, some have sought to distance themselves from the former president and the riot itself. 

"Nearly three years ago today, I made some choices I sincerely regret," Christopher Worrell, a Florida man who was sentenced to 10 years in prison, said earlier this week. He was convicted of numerous counts including assaulting officers. 

Other defendants, however, have continued to embrace the claims of a stolen election, even in the face of prison time. Minutes after being sentenced to 10 years in prison for his role in the attack, Proud Boys member Dominick Pezzola — who was seen in a widely-shared video breaking a Senate wing window with a police riot shield — raised his fist into the air and shouted "Trump won" as he was led out of court. 

Over the last three years, it has been the federal judges, however, who have delivered the starkest messages to defendants and the public about the Capitol breach.

Judge Tanya Chutkan, who is overseeing Trump's criminal prosecution, said of the attack in one sentencing hearing, "This was no exercise of First Amendment rights. It was a violent attempt to overthrow the government." 

And in sentencing Rhodes, the Oath Keepers founder, after he was found guilty of seditious conspiracy, Judge Amit Mehta reflected on the consequences of the Capitol attack. 

"We all now hold our collective breaths with an election approaching.  Will we have another Jan. 6? That remains to be seen," the judge said.

Scott MacFarlane, Melissa Quinn, Andres Triay, and Keshia Butts contributed to this report. 

Robert Legare

Robert Legare is a CBS News multiplatform reporter and producer covering the Justice Department, federal courts and investigations. He was previously an associate producer for the "CBS Evening News with Norah O'Donnell."