In one post, a rioter pardoned by President Donald Trump after taking part in the storming of the Capitol expressed his “joy and happiness” at just how badly prosecutors who worked on cases like his own were “hurting right now” after some of them were fired.

In a different post, another pardoned rioter taunted agents who worked on investigations linked to the events of Jan. 6, 2021, ridiculing them for worrying that they would be revealed and asking sarcastically, “Why would you be afraid of us knowing your names?”

In a third post, yet another rioter granted clemency by the president featured the image of a document that clearly showed the name and cellphone number of the FBI agent who oversaw his case.

In the past few weeks, an increasing number of Jan. 6 defendants who benefited from Trump’s mercy have gone on the attack on social media, lashing out at the agents and prosecutors who worked on their criminal cases. The pardoned rioters have assailed these law enforcement officials as “traitors” or “evil,” often doxxing them by posting their names, photos and contact information online.

Many of the messages are likely protected by the First Amendment, and, at least for now, there is no indication that they have led to any violence.

But the posts also suggest a mounting and disturbing desire for revenge on the part of the pardoned rioters, and experts have raised concerns that the frequency and number of the digital attacks could increase the risk that violence might eventually occur.

“The bottom line is, it’s extremely dangerous,” said Robert Pape, a political scientist at the University of Chicago who has studied the Jan. 6 defendants for more than four years. “Research tells us that efforts like this help to make it seem as if targeted attacks are actually popular and have a mantle of legitimacy. That itself could nudge assailants over the edge.”

The torrent of online anger comes as many of the federal officials subject to it were already under pressure from the Justice Department itself.

More than a dozen prosecutors who worked on Jan. 6 cases were recently fired from the U.S. attorney’s office in Washington, and the department has sought information about thousands of FBI agents and employees who worked on Capitol riot investigations.

Those moves have left many law enforcement officials feeling as if the agencies that employ — or employed — them no longer have their backs. And their sense of disappointment only deepened last week after the new U.S. attorney in Washington, Ed Martin, vowed to investigate a different set of threats: those that were reportedly made against employees working for Trump’s close ally Elon Musk.

“There is certainly a lack of public support for Jan. 6 prosecutors and agents from political appointees in the Justice Department,” said Alexis Loeb, a former federal prosecutor who supervised many Capitol riot cases. “But there are still people in the department and the FBI who recognize that threatening people just for doing their jobs is simply wrong.”

Inside the FBI, agents and others who worked on the cases are deeply concerned about losing their jobs but also fear for their personal safety, given that the Justice Department asked for names of employees who handled the Jan. 6 investigations and a terrorism case. The inquiry into the riot became the department’s largest, leading the FBI to open about 2,400 cases, more than half of which resulted in charges being filed.

Brian Driscoll, the FBI’s acting director, said in an email Thursday to bureau employees that the Justice Department was aware of the “risks posed to you and your families should these lists become public.”

He noted that FBI personnel could become victims of doxxing or swatting, when false emergency calls are placed with the intention of drawing a heavily armed police response. He also pointed to internal guides that FBI personnel can use to reduce their digital footprints, making it harder to be targeted.

The attacks by Jan. 6 defendants against federal law enforcement were only the latest in a series of such assaults reaching back to Trump’s first term in the White House.

In August 2022, after the FBI found reams of classified material during a court-authorized search of Mar-a-Lago, Trump’s private club and residence in Florida, social media erupted with outraged posts by Trump supporters. One of those supporters, Ricky W. Shiffer, was so angered by the search that he tried to break into an FBI field office near Cincinnati and ended up being killed in a shootout with the local police.

Something similar but less dramatic happened this spring after Trump was convicted of 34 felony counts at a criminal trial in New York City. After the verdict, pro-Trump forums online erupted with hateful messages about the jurors in the case and apparent attempts to leak their personal information.

“Hope these jurors face some street justice,” one anonymous user of a forum wrote. “Wouldn’t be interesting if just one person from Trump’s legal team anonymously leaked the names of the jurors?”

Last weekend, Trump’s new homeland security secretary, Kristi Noem, made claims on social media that the “corrupt” FBI was behind a recent leak revealing that a “large scale” immigration enforcement action would soon take place in Los Angeles.

“We will work with any and every agency to stop leaks and prosecute these crooked deep state agents to the fullest extent of the law,” Noem wrote.

Loeb began seeing messages targeting her online even before Trump offered clemency to all of the nearly 1,600 people charged in connection with the Capitol attack. After a right-wing journalist posted on social media in December that she was leaving her job as a federal prosecutor before the change in administrations, she experienced a surge in attacks, including one post that identified her by name above an image of gallows.

“That’s the cure for corruption,” the caption said.

But the volume of posts increased sharply after Trump’s reprieves, which seemed to embolden many of the defendants. Some began assembling lists of agents and prosecutors, collecting names and photos from their compatriots.

When one of the defendants asked online on Monday whether he should build “a public database” listing the names of all the Jan. 6 prosecutors and agents, he got dozens of affirmative responses.

“I can contribute,” one of his fellow defendants replied.

“I am going to get my popcorn ready,” another wrote.

In the immediate aftermath of Trump’s clemency grants, two of the country’s most prominent right-wing extremists — Enrique Tarrio of the Proud Boys and Stewart Rhodes of the Oath Keepers — asserted that they wanted Trump to seek revenge on their behalf against the investigative teams that worked on Jan. 6 cases.

“Success,” Tarrio said at the time, “is going to be retribution.”

Last week, Pam Bondi, the new attorney general, started what appeared to be the first step toward that goal when she announced the formation of a “weaponization working group” inside the Justice Department.

One of the group’s missions, Bondi said, would be to examine what she described as the “improper investigative tactics and unethical prosecutions” arising from the department’s Capitol attack prosecutions.

How she had reached those conclusions remains unclear.