Washington — Department of Homeland Security Secretary Alejandro Mayorkas called the social media rhetoric “extraordinarily alarming” that followed the killing of UnitedHealthcare CEO Brian Thompson earlier this month, warning of the risk of violent extremism it poses. 

Mayorkas said in an interview that aired on “Face the Nation with Margaret Brennan” that he’s “alarmed” by the “heroism that is being attributed to an alleged murderer of a father of two children on the streets in New York City,” as the the insurance executive’s killing in midtown Manhattan on Dec. 4 has prompted scattered celebration on social media — and lionizing of the man charged in the deadly shooting.

“It speaks of what is really bubbling here in this country, and unfortunately we see that manifested in violence, the domestic violent extremism that exists,” Mayorkas said.

Luigi Mangione, the 26-year-old suspect, faces federal charges including murder. Investigators’ working theory of the motive is animosity toward the health care industry. On social media, support for the suspect has materialized surrounding grievances toward perceived inequalities in the insurance and health care systems.

Mayorkas said the department sees a “wide range of narratives” that “drive some individuals to violence.” 

“We’ve seen narratives of hate. We’ve seen narratives of anti-government sentiment. We’ve seen personal grievances in the language of violence, accompanying or being a part of those narratives,” Mayorkas said. “it’s something that we’re very concerned about — that is a heightened threat environment.” 

The Homeland Security secretary said the threat of domestic violent extremism “is one of the great threat streams that we must counter.” And he noted that DHS has been concerned about social media rhetoric “for some time.”

Still, Mayorkas, whose tenure at the helm of the department is coming to an end next month, said that while his faith in the American people is “rattled” by incidents like the “cold-blooded murder of a United Health Care executive,” he noted that “that’s the actions of an individual, not reflective of the American public and of the democracy in which we live.”

“I have faith in the American people,” Mayorkas added.