For some Americans on the far right, Charlie Kirk died a"martyr" and any criticism of the hugely popular conservative activist must be punished.

Online vitriol and grassroots persecution have exploded in the wake of the assassination of the 31-year-old,who had been an electrifying presence on the US right.

Laura Sosh-Lightsy, assistant dean of students at a university in the southern state of Tennessee, found herself in hot water after posting on social media about Kirk's death.

"Hate begets hate. ZERO sympathy," she said on Facebook after the killing, which happened Wednesday in front of a large crowd at a university in Utah.

Republican US Senator Marsha Blackburn quickly called out the comment – and Sosh-Lightsy.

"This person should be ashamed of her post. She should be removed from her position," the Tennessee lawmaker said.

Middle Tennessee State University's president announced that same night an employee's firing for a"callous" comment about Kirk.

Kirk, who rallied his millions of followers to help President Donald Trump win a second White House term, was both revered and reviled for his pro-gun, anti-abortion and anti-immigrant rhetoric.

Shooting suspect Tyler Robinson, who was arrested Thursday, is said to have engraved anti-fascist and meme-culture messages on his bullet casings. This has led to a large part of the American right labelling him a"far-left" killer. Authorities have not provided many details about why they think Robinson carried out the attack on Kirk.

Some Kirk supporters have turned into online sleuths, searching out accounts that praised or celebrated Kirk's murder.

"If they have their picture on their profile, even without a name, download the picture and reverse image search it," conservative influencer Joey Mannarino said.

"Cross-reference it with their LinkedIn profile and find their place of employment. Call the place of employment, leave Google reviews."

Fallout

These efforts have targeted teachers, firefighters and even military personnel, some of whom have lost their jobs.

MSNBC political analyst Matthew Dowd lost his job shortly after on-air comments about Kirk, one of the first of many figures to experience similar fallout.

Office Depot said Friday that it fired a worker at a Michigan store who was seen on video refusing to print flyers for a Kirk vigil and calling them “propaganda”.

Several Delta Air Lines employees were also suspended after social media posts that “went well beyond healthy, respectful debate”, CEO Ed Bastian said in a message to the company.

Kirk's murder has been condemned by both sides of the political aisle. But Trump quickly blamed the country's"radical left", even as authorities were only just launching a manhunt for the killer.

Online trackers have targeted an Oklahoma teacher, who posted on social media:"Charlie Kirk died the same way he lived: bringing out the worst in people."

That teacher has since been investigated by the state's Department of Education, which described his comments as"abhorrent".

Murder of Charlie Kirk: 'There's way too much political violence in the US'

Florida Governor Ron DeSantis’ education commissioner warned teachers in the state that making “disgusting” statements about Kirk’s assassination could draw sanctions, including the suspension or revocation of their teaching licenses.

“Most people think they have a right to free speech … but that doesn’t necessarily apply in the workplace,” said Vanessa Matsis-McCready, associate general counsel and vice president of HR Services for Engage PEO. “Most employees in the private sector do not have any protections for that type of speech at work.”

She said that employers were increasingly worried about the impact that their workers' public comments could have on a company's brand.

“Some of the individuals that had posted and their posts went viral, all of a sudden the phone lines of their employers were just nonstop calls complaining,” Matsis-McCready said.

Stadium memorial service

Trump, who praised Kirk as a"giant of his generation", has led the US government in memorialising the activist, with high-ranking US officials working to weed out critics of Kirk and his legacy.

Trump ordered flags lowered to half-staff in honour of his ally, and Kirk's body was flown from Utah to his home in Phoenix, Arizona aboard Air Force Two, escorted by Vice President JD Vance.

Meanwhile, Defense Secretary Pete Hegseth ordered members of the military to identify colleagues who mocked or celebrated Kirk's death.

US Under Secretary of State Christopher Landau declared that"foreigners who glorify violence and hatred are not welcome visitors to our country".

"I have been disgusted to see some on social media praising, rationalising, or making light of the event, and have directed our consular officials to undertake appropriate action," he said in a post on X.

"Please feel free to bring such comments by foreigners to my attention so the @statedept can protect the American people."

Laura Loomer, a far-right conspiracy theorist who has Trump's ear, has been one of the most high-profile attackers of Kirk's critics.

She denounced an employee of the Federal Emergency Management Agency (FEMA), who had expressed disgust on Instagram that flags would be lowered for"the literal racist homophobe misogynist".

Loomer shared the staffer's LinkedIn profile and said:"These people hate us. They don't belong near the levers of our National Power."

Following Loomer's post, FEMA said the employee was placed on leave for making"revolting and unconscionable" comments.

On Saturday, Kirk's organisation Turning Point USA announced a memorial service for its founder will be held on September 21 in a suburb of Phoenix.

The chosen venue hints at the expected turnout: a stadium normally home to a professional football team, with a seating capacity of more than 63,000.