A former army reservist's right to express his views, however repugnant, doesn't trump the risk he might try to escape justice, a U.S. district court judge declared Wednesday as he ordered accused white supremacist Patrik Mathews of Beausejour, Man., to remain behind bars.

Judge Timothy Sullivan said Mathews, 27, is in the country illegally, has no ties to the United States and is facing serious charges that stem from his role in an alleged plot to sow violence, death and racial unrest, including at a massive pro-gun rally earlier this week in Virginia — a plot assistant U.S. attorney Thomas Windom described in court as domestic terrorism.

"You can't get more serious than murder," Windom told Sullivan as he argued the government's case to keep Mathews in custody. "You can't get more serious than inciting civil disobedience. That's exactly what Mr. Mathews was planning to do."

Sullivan — who sounded disinclined throughout Wednesday's brief hearing to free the accused, given that he's in the country illegally as it is — agreed. He ordered Mathews held until a preliminary hearing scheduled for Jan. 30.

"I don't need to go any further than he's a serious risk of flight," Sullivan said. "This is a very dangerous person, he espouses very dangerous beliefs — I don't think I have to say much more."

After court Wednesday, Robert Hur, U.S. attorney for the district of Maryland, spoke to reporters about the type of danger Mathews presents, citing the acquisition of long guns and ammunition, receiving training with other members of The Base — a violent neo-Nazi paramilitary group — and packing food and supplies in a truck "for the war" in Virginia.

"These defendants did more than talk. They took steps to act and act violently on their racist views," Hur said.

"Put simply, this domestic terrorism investigation likely saved lives," added David Weiss, U.S. attorney for the district of Delaware.

FBI special agent in charge Jennifer Boone said radicals like Mathews are domestic adversaries who hide in plain sight.

"What sets him apart is the desire to do harm to those who do not look like them, or believe as they believe," Boone said. "We must not allow fear or silence to be weaponized by those who seek to commit acts of violence against our communities or against our nation."

Disappeared from Manitoba

Mathews and two other men were arrested last week after the former reservist disappeared from his residence in Manitoba amid allegations he was a recruiter for a white-supremacist group called The Base. At the time, Mathews was a combat engineer with the 38 Canadian Brigade Group in Winnipeg, though the military said then it was investigating those allegations and fast-tracking his request to be released from the military.

He is facing one count of transporting a firearm and ammunition with intent to commit a felony and one charge of being an alien in possession of a firearm and ammunition — charges that each carry a maximum of 10 years in prison, three years of probation and a $250,000 fine.

Mathews is seen in a still from a video in which U.S. federal prosecutors say he calls for violent revolution. (U.S. Attorney detention memo)

Prosecutors allege in documents filed in court that Mathews videotaped himself advocating for killing people, poisoning water supplies and derailing trains. They have also alleged that Mathews and two other alleged co-conspirators and Base members, had been planning to violently disrupt Monday's gun-rights rally in Richmond, Va., in hopes of inciting civil war.

Defence counsel Joseph Balter acknowledged early in the hearing that his client, if released, would be immediately subject to an immigration warrant. But he argued that the government's motion to keep Mathews in custody was predicated more on the content of "odious" and "repugnant" sentiments expressed in the video than on the potential danger he potentially posed.

The charges he is facing "would not, by themselves, support a detention order," Balter said. "One man's domestic terrorism can be another man's exercising of his First Amendment rights."

The detention memo filed Tuesday details how investigators used a hidden camera and microphone in a home in Delaware to record Mathews talking about the Virginia rally as a "boundless" opportunity.

"All you gotta do is start making things go wrong and if Virginia can spiral out to [expletive] full-blown civil war," the documents quote Mathews as saying.

'Need to claim my first victim'

Mathews and Brian Mark Lemley Jr., 33, of Elkton, Md., planned violence at the Richmond rally, according to prosecutors. They said Lemley talked about using a thermal imaging scope affixed to his rifle to ambush unsuspecting civilians and police officers.

"I need to claim my first victim," Lemley said on Dec. 23, according to the memo.

"We could essentially like be literally hunting people," Mathews said, according to prosecutors. "You could provide overwatch while I get close to do what needs to be done to certain things."

FBI agents arrested Mathews, Lemley and William Garfield Bilbrough IV, 19, of Denton, Md., last Thursday as part of a broader investigation of The Base. Authorities in Georgia and Wisconsin also arrested four other men linked to the group.

Mathews, who was ushered into court wearing orange prison garb, with his hands cuffed behind his back, was silent throughout Wednesday's hearing except when Windom made passing reference to the fact that Mathews couldn't provide the address of the farm where he said he lived in Manitoba.

"I just couldn't remember the street address, sir," Mathews interjected, a note of frustration in his voice.

Sullivan admonished him for speaking out, urging him to relay his messages through Balter and otherwise "take shelter under your Fifth Amendment right to remain silent."

A former army reservist's right to express his views, however repugnant, doesn't trump the risk he might try to escape justice, a U.S. District Court judge declared Wednesday as he ordered accused white supremacist Patrik Mathews of Beausejour, Man., to remain behind bars. 2:18

Monitoring The Base

Megan Squire follows The Base online and said there was a lot of chatter about attending the rally in Virginia that stopped after last week's arrests.

"It got very quiet on Telegram while these guys tried to figure out what was going to happen, if it was serious," said Squire, a computer scientist who teaches cybersecurity and online extremism at Elon University in North Carolina.

Part of her job is to collect large amounts of data from online sources, to understand the phenomena of online hate, radicalization and extremism.

Megan Squire is a computer scientist who teaches online extremism and security. She researches and collects data in dark places on the internet and has been following The Base for some time. (Submitted by Megan Squire)

"They started disavowing the rally. 'Don't go, you know, it's a Fed honey pot' and all this kind of stuff. Really backtracking from that position.… It was very obvious that they knew about the arrests and they were trying to figure out how it affected them and how it impacted them and possibly their attendance at a real-world event," Squire said.

The group appears to be in some disarray now, she said.

"When they're not in-fighting with each other, they're accusing each other of being federal agents, accusing other groups of being infiltrated," she said.

"They read the [court] filings and the motions, some of them, just as closely as we do to try to understand, because they're trying to see where their weak spots are, who they shouldn't have trusted."