When Vem Miller was stopped, police said they discovered his black SUV was unregistered and his loaded firearms unknown to the state.
There were also a fake passports, identity documents and press credentials.
Chad Bianco, the Riverside County Sheriff, said the finds were typical of a “sovereign citizen” — someone who does not believe in government control.
“They are certainly considered a far-Right group,” Mr Bianco added.
Mr Miller, 49, of Las Vegas, was named as the man whom the police chief said was a would-be assassin arrested less than a mile from Donald Trump’s campaign rally in Coachella on Saturday.
His vehicle was stopped because it was fitted with a homemade number plate, which Mr Bianco said was “indicative of a group of individuals that claim to be sovereign citizens”.
Counterfeit passports and driver’s licences featured different names to the one he gave authorities.
And then there was a loaded handgun and a shotgun, said to not properly be registered, which was given as the reasoning for Mr Miller’s arrest.
Mr Bianco said that his local law enforcers had “probably stopped another assassination attempt”.
Accusations are complete bull–t
In an interview with a local journalist following his release on bail, Mr Miller said he would never harm Trump, whom he supports in the upcoming presidential election.
“These accusations are complete bull—t,” Miller told Southern California News Group on Sunday.
“I’m an artist, I’m the last person that would cause any violence and harm to anybody.”
Mr Miller said he had a “special entry pass” to the Trump rally, in contradiction to police claims.
The pass, the 49-year-old said, was handed to him by an associate in the Republicans, while he claimed he attended another campaign event in Nevada with firearms in his vehicle without any trouble.
Mr Miller is a registered Republican and ran for Nevada state assembly in 2022, local media outlets reported.
Campaign material issued by a man with the same name promised to “restore our constitutional rights”, including references to the Second Amendment on the right to bear arms.
There were also pledges to “revitalise small business, which was so grossly harmed by the Covid mandates” and “give power back to parents, who have had their voices ignored by authoritarian school boards”.
The FBI describes the sovereign citizens movement as a domestic terror threat, similar to eco-terrorists and animal rights extremists.
The agency says the movement’s participants likely believe that even though they reside in the United States, they are separate or “sovereign” from the government.
According to the Press Enterprise, Miller denied that he was part of the sovereign citizen group.