In striking and chilling terms, several career Justice Department officials on Thursday offered dire warnings about the online extremist network “764,” whose young followers around the world use popular social media platforms to target, groom and push vulnerable teens into harming themselves and others.

“I don’t think Stephen King is dark enough to come up with some of the stuff that these kids are coming up with,” said Justin Sher, a trial attorney with the Justice Department’s National Security Division.

“It is as serious a threat as you can imagine,” Sher’s Justice Department colleague James Donnelly said. “[And] they’re trying to metastasize the evil.”

Their comments came during a panel about 764 hosted by George Washington University’s Program on Extremism. It was a rare public appearance for two career prosecutors that the panel’s moderator described as “the point people” on 764 within the department’s National Security Division.

Sher and Donnelly both noted that 764 members are increasingly trying to push victims to take deadly actions, including suicide or school shootings and other mass-casualty attacks.

As ABC News has previously reported, 764 members find vulnerable victims on popular online platforms, elicit private information and intimate sexual images from them, and then use that sensitive material to threaten and blackmail victims into mutilating themselves, harming others, or taking other violent action — all while streaming it on social media so others can watch and then disseminate recordings of it.

“For them, content is currency,” Sher said. “So they are building their content inventory … and putting it out there to build their status within these groups.”

While anyone can be targeted, 764 members often “systematically target underage females,” especially those already struggling with depression, eating disorders or other mental health issues, according to an FBI agent’s description of 764 in charging documents from a recent case in Tennessee.

“[764] actors often groom their victims by first establishing a trusting or romantic relationship before eventually manipulating and coercing them,” the agent wrote. “Extremists control their victims through building immense fear,” and they do it simply “for the network’s entertainment or threat actor’s own sense of fame,” the agent said.

The National Center for Missing and Exploited Children says it received more than 2,000 reports of abuse tied to 764 or similar networks in the first nine months of this year — double the number of reports it received last year.

In the Tennessee case, during the summer of last year, 19-year-old Cayden Newberry of Johnson City and others associated with 764 allegedly forced a 13-year-old girl from Raritan, New Jersey — hundreds of miles away — to carve their initials into her leg and then send pictures and videos of it to them. The young victim later learned that many of them shared the content with the so-called “boss” of a 764-related group on Discord so they could be admitted into the group, charging documents allege.

At one point, Newberry allegedly used DoorDash to have a cell phone purchased at Target and then delivered to the girl’s home “so they could exclusively and discreetly communicate,” according to the charging documents.

Newberry was first arrested last month and indicted last week on two counts related to child exploitation.

During Thursday’s panel, Sher explained that many members of 764 and similar networks have a particularly concerning goal — which is why the Justice Department’s National Security Division and FBI are now paying such close attention to 764.

“Their objective is … to cause the downfall of society, cause the downfall of the U.S. government,” Sher said of 764 and similar networks. “They want a Darwinian society, they want one that is survival of the fittest.”

The FBI is investigating more than 350 people across the United States with suspected ties to 764 or similar networks. And the Justice Department has already publicly charged at least 37 such people in recent years, including Newberry.

Their victims have been as young as nine years old, according to authorities.

Career Justice Department officials on Thursday’s panel agreed that current U.S. law can make it harder to prosecute 764-related cases.

“Coercing a minor to engage in self-harm or to harm another is not necessarily criminalized in an easy way,” said Steve Grocki, the chief of the Justice Department’s Child Exploitation and Obscenity Section. “It is challenging to some extent.”

But he said federal prosecutors try to “be creative” and find ways to use existing laws, even as some in Congress are trying to pass new laws that would address the specific conduct of online extremist networks like 764.

An assistant U.S. attorney with the U.S. Attorney’s Office for the Northern District of Illinois in Chicago, Kavitha Babu, also noted that federal prosecutors are “often” hesitant to prosecute minors, which presents a challenge to taking on 764 since so many minors are being victimized by fellow minors. But she said that she and other prosecutors are now “taking a harder look” at whether federal charges might be warranted in cases involving minors.

Thursday’s panel was held just hours before a 19-year-old man from San Antonio, Texas, admitted in federal court that, through his actions with 764, he took part in a criminal enterprise and racketeering conspiracy.

According to documents filed in court, Alexis Aldair Chavez began consuming violent 764-related content on the online platforms Discord and Telegram in 2022, and he eventually “earned the right” to speak with other 764 members “by killing his cat, recording the killing, and posting it [online] for others to see.”

Over the next nearly two years, he allegedly groomed several young girls around the world for extortion and self-mutilation. He allegedly pushed one young girl to light her arm on fire during a recorded video call and forced another young girl to create an 18-minute video that showed her harming herself in horrific and sexually-explicit ways, including with a dead rat that had been in a jar, suspended in solution.

The video showed her “crying out in pain as the solution on the dead rat burned” her, according to court documents.

By June 2024, Chavez was allegedly acting as an administrator for various 764 subsidiaries online. He was arrested in October 2024, and pleaded guilty late Thursday to one count of participating in a racketeering conspiracy, one count of distributing child pornography, and one count of possessing child pornography.

764 was first launched by a 15-year-old in Texas, Bradley Cadenhead, who named it after the first three digits of his ZIP code. Since then, 764 has spread around the world, growing into more of an ideology than a singular group, experts say. And other groups, inspired by 764, have formed with different names but identical tactics and goals.

“764 is sort of the big brand name. And if content is in fact their currency, 764 has the biggest war chest,” Sher said.