A Virginia man has been charged with making violent threats on social media against Kamala Harris shortly after she began her campaign for president.
Frank Carillo, 66, of Winchester, faced court on Monday over threatening messages posted on GETTR, a conservative microblogging website.
One stated Ms Harris "needs to be put on fire alive", while another stated she would "regret ever trying to become president".
Mr Carillo was arrested on 2 August. FBI agents seized an AR15-style rifle, a handgun, and thousands of rounds of ammunition in a search of his home.
Investigators allege that Mr Carillo did "knowingly and willfully make a threat to take the life of and to inflict bodily harm" against Ms Harris.
The federal complaint says 4,359 messages were found threatening various people or groups, including 19 directed at Ms Harris.
Court documents showed other messages included "AR15 locked and loaded", and threats to "kill all Muslims" and shoot "illegals... in the head".
The messages in the documents relating to Ms Harris are from 27 July - the date of her first campaign fundraiser and less than a week after Joe Biden dropped out of the presidential race and endorsed her.
"This is ridiculous, for a comment," Mr Carillo said during the search of his home, according to the documents. "I guess I'm gonna need a lawyer."
Making a threat against the president, vice-president or others in the line of presidential succession carries a prison sentence of up to five years.
The investigation began after the recorder's office in Arizona's Maricopa County reported threats against the county recorder, Stephen Richer, who was known for pushing back against false claims of election fraud four years ago.
GETTR and Google helped the FBI in its investigation.
Republicans and Democrats have condemned the growing trend of political violence, especially after last month's assassination attempt on Donald Trump, who was injured in the attack.
GETTR was originally founded by Jason Miller, Trump's chief spokesperson. He left when he joined the 2024 Trump presidential campaign last year.
Mr Carillo has requested a lawyer and will next appear in court on Thursday.