A Boston man who was falsely identified as the gunman in the Parkland school shooting by the conspiracy theory website InfoWars has filed a defamation suit against the site and its creator, Alex Jones, contending that the posts have exposed him to damaging volleys of online abuse and threats that show no sign of slowing down.

“Many harassers seem to believe my client is part of a false flag operation conducted by ‘the deep state’,” said attorney Mark Bankston, who is representing 24-year-old Marcel Fontaine in the suit filed on Monday in Travis county, Texas, where InfoWars is based.

A picture of Fontaine, wearing a “communist party” T-shirt began circulating in certain internet circles, most likely originating on the message board site 4chan, in the immediate aftermath of the shooting.

One of the original internet message board posts of Fontaine suggesting he was the shooter. Fontaine has never been to Florida. Photograph: Courtesy Mark Bankston

The popular T-shirt depicts famous 20th-century communist leaders Stalin, Lenin, Mao and Fidel Castro drinking from red Solo cups and wearing novelty party hats. Karl Marx, author of the Communist Manifesto, is depicted with a lampshade on his head. Despite the shirt’s clearly ironic intent, InfoWars ran a headline that incorrectly identified Fontaine’s image as that of the shooter and said he “dressed as communist”.

InfoWars, Bankston noted, boasts an online readership of more than 30m page views a month, which puts it on par with a number of mainstream outlets. MSNBC.com, by comparison, sees about 40m page views. “The total number of people who saw the false accusation as a result of InfoWars’ mass dissemination and endorsement … would be measured in the hundreds of millions,” the suit reads.

Jones, a popular internet conspiracy theorist, is especially fond of painting mass casualty events that command public attention as “false flag” operations coordinated by the government or other shadowy power figures. He also often describes elaborate, fanciful conspiracies wherein the families of victims in such events are fake paid “grief actors”.

That’s part of the reason, Bankston argues, that the false ID is so insidious in this case, beyond an ordinary reporting error. “Because InfoWars advises its audience to distrust mainstream media sources, the subsequent mainstream news reports,” which identified Nikolas Cruz, who has been charged with murder, as the alleged shooter, “did not remove the threat to Marcel Fontaine”, the suit notes. “It is no exaggeration to say that Plaintiff’s life remains in genuine peril.”

The filing is one of at least two active defamation suits pending against Infowars by plaintiffs who say his site has unleashed a barrage of online abuse at them from Jones’s credulous followers. The first, filed just three weeks ago, came from a counter-protester at the 2017 Charlottesville white supremacist rallies who filed and posted video of an attacker barreling through protesters, killing Heather Heyer and injuring others.

A request for comment to InfoWars was not immediately returned.