Free speech may be sacred in the United States but calling for the killing of US lawmakers on social media is unlawful, a New York jury ruled Wednesday after a weeklong trial that revisited the January 6 riot at the Capitol.

The federal trial, the first related to the storming of Congress by supporters of ex-president Donald Trump, was viewed as a test case for the limits of freedom of expression protected by the First Amendment of the US constitution.

After just three hours of jury deliberations, Brendan Hunt, a 37-year-old court employee who uses the alias "X-Ray Ultra," was found guilty of threatening to murder elected officials including Democratic congressional leaders Nancy Pelosi and Chuck Schumer, and progressive congresswoman Alexandria Ocasio-Cortez.

He was convicted of an "intent to impede, intimidate and interfere" with the performing of their official duties, specifically Congress's vote on January 6 that confirmed President Joe Biden had won November's election over Trump.

Hunt was also charged with "intent to retaliate" over the electoral college vote count, which affirmed that Trump would have to leave the White House after just one term.

The charges related to several messages that Hunt posted on social networks. The first dated back to December 6 when, on Facebook, he called on Trump "to hold a public execution of pelosi aoc schumer etc."

"And if you dont do it, the citizenry will," he wrote.

"Start up the firing squads, mow down these commies, and lets take america back!"

On January 8, two days after Trump supporters stormed the Capitol to try to stop the count, Hunt posted an 88-second video on BitChute, a platform beloved by the far right, titled "KILL YOUR SENATORS."

"We need to go back to the U.S. Capitol when all of the Senators and a lot of the Representatives are back there, and this time we have to show up with our guns," he said, addressing the camera.

Hunt, using a number of expletives, added that he would "go there myself and shoot them and kill them."

It was because of the video message that the jury found Hunt guilty, a spokesman for prosecutors said after the verdict.

The FBI has arrested more than 400 people in relation to the January 6 violence, which Biden called "an insurrection."

Among the thousands of calls they received was one alerting them to Hunt's video.

Brendan Hunt, 37, appears in a screenshot of a video he posted titled "Kill your senators"
Brendan Hunt, 37, appears in a screenshot of a video he posted titled "Kill your senators" US Attorney's Office / Handout

Hunt, the son of a retired judge, calls himself an actor, musician and journalist. He was arrested at his home in the New York borough of Queens on January 19, the day before Biden's inauguration.

Officers did not find any weapons, or evidence of involvement or communication with any extremist groups.

Prosecutors did not claim that Hunt, who read "Mein Kampf" and called on Trump to seize power "like Hitler," was in Washington on January 6 or even that he intended to go.

The trial focused on whether Hunt's threats were serious and whether he really intended to attack elected officials as prosecutors argued.

Hunt's court-appointed lawyer Leticia Olivera said the messages were just "a nonsense rant" that were constitutionally protected free speech.

She argued that they should not have been taken seriously given that Hunt had admitted alcohol problems and his video channel only had 99 subscribers.

"As nonsensical and offensive as it may be, he has the right to say these things," Olivera told the trial, adding that "no one" took the posts seriously and Hunt himself removed his video from BitChute the next day.

Prosecutor David Kessler said in closing arguments Wednesday that "the first amendment does not protect" against such threats.

"The government does not need to prove that the defendant attempted to kill. Making the threat is the crime," even if it is made on social networks and not addressed directly to the people targeted, he added.

The jurors, who were made to watch a video of the attack on the Capitol and who listened to evidence by a police officer who was there that day, ultimately agreed with the prosecution.

But experts expect the verdict to be contested in a country where the constitution is sacrosanct.

"On appeal, I am sure the free speech issue will be raised," Dmitriy Shakhnevich, a criminal law professor at New York City University, told AFP.

Hunt faces up to ten years in prison.