Heroism attributed to suspect Luigi Mangione alarming – Mayorkas

Mr Thompson, the 50-year-old CEO of the largest US health insurer UnitedHealthcare, was gunned down outside a Manhattan hotel early on 4 December triggering a massive manhunt for the killer.

Mr Mangione, 26, was arrested days later in Pennsylvania and flown to New York where he is facing both federal and state charges, including first-degree murder in furtherance of terrorism.

Investigators accuse him of carrying out a targeted killing, pointing to evidence that suggests a long-held animosity towards the US healthcare industry. On social media, support for Mr Mangione has often been accompanied by grievances and complaints with the health insurance sector.

“We have been concerned about the rhetoric on social media for some time,” Mayorkas said on Sunday. “We’ve seen narratives of hate. We’ve seen narratives of anti-government sentiment. We’ve seen personal grievances in the language of violence.”

Mayorkas, whose homeland security department is in part responsible for protecting Americans from domestic terrorism, said his department sees a “wide range of narratives” that “drive some individuals to violence.”

“It’s something that we’re very concerned about,” he said. “That is a heightened threat environment.”

But the 65-year-old, whose time at the helm of the department will end next month, stressed that Mr Thompson’s killing was “the actions of an individual [and] not reflective of the American public”.