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David Holden, the president of a small synagogue in rural Michigan, had never heard of The Base until his house of worship was defaced last fall.

Vandals targeted Temple Jacob, one of the oldest continuously operating synagogues in the state, by spray-painting swastikas and two SS bolts in black, and authorities believed that members of The Base, a neo-Nazi network, were behind the anti-Semitic graffiti.

The jarring incident came flooding back to Holden after he learned of the arrests Thursday of three alleged members of the group in a separate case on the East Coast, which has put a renewed focus on the largely decentralized movement spanning chapters in North America and around the world.

The FBI's pursuit of alleged members of the group widened, with authorities in Georgia announcing charges Friday against three additional men accused of belonging to The Base and plotting to overthrow the government and murder a couple.

Luke Austin Lane, 21; Michael John Helterbrand, 25; and Jacob Kaderli, 19, were charged with conspiracy to commit murder and participation in a criminal gang, according to police in Floyd County. Investigators said the men targeted a couple because Lane, Helterbrand and Kaderli suspected them of being active in the liberal antifa movement.

A fourth man was also arrested this week in connection with The Base.

Yousef Omar Barasneh, 22, from Wisconsin, allegedly traveled to Silver Creek, Georgia, in September to train with other members of The Base, including those arrested Thursday. According to the criminal complaint, Barasneh conspired to vandalize minority-owned properties in what the group called "Operation Kristallnacht," a reference to night raids conducted by German Nazis against Jewish homes and businesses in 1938.

Members of The Base allegedly spray-painted at least one synagogue in Racine, Wisconsin, with swastikas and anti-Semitic language, officials said. Authorities suspect the case is linked to the one at Temple Jacob.

"We welcome the arrests," Holden said Friday. "As a first-hand witness to their mischief-making, I can easily believe law enforcement has good reason to be concerned."

But experts who track hate groups say the vandalism in Michigan is merely a tamer example of the larger, apocalyptic vision that members harbor: Their ideology supports a race war against minorities and the establishing of white ethno-states. The group's name is the English translation of al Qaeda, according to The Soufan Group, a nonprofit security intelligence firm.

"Just like al Qeada, The Base does not believe in any political solution to what they see as a threat to the white race," said Mollie Saltskog, an intelligence analyst with the firm. "Violence is the only option."

Saltskog said that while the ideologies of a white supremacist group such as The Base and a jihadist organization such as al Qaeda appear disparate, their shared desire for bloodshed only incites their followers.

"They feed off each other in a pretty sick way," she added.

The Base, which took root about two years ago, maintains it is not a political organization and denies being a paramilitary group or militia with no formal membership or official leadership.

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Its membership numbers are unclear, but Saltskog said The Base's chapters extend beyond the United States and Canada, with support in Europe and Australia.

One of those arrested in the U.S. this week is Canadian national Patrik Mathews, 27, who was allegedly a main recruiter for the group in Winnipeg.

Mathews was a combat engineer in the Canadian Army Reserve, and his disappearance last summer put a spotlight on the group's efforts to attract new blood and its use of paramilitary training camps.

Federal prosecutors say Mathews illegally crossed into Minnesota in August, and was picked up by two men from Maryland: Brian Lemley, Jr., 33, and William Bilbrough IV, 19.

In December, Mathews and Lemley, a former cavalry scout in the U.S. Army, constructed a functioning assault rifle, according to an affidavit, and the men bought 1,650 rounds of ammunition this month and used the assault rifle at a Maryland gun range.

Law enforcement officials said they moved in to arrest the men after learning they planned to attend the upcoming gun-rights rally at Virginia's state Capitol in Richmond. Gov. Ralph Northam has declared a state of emergency for the event after receiving "credible intelligence" that armed militias and hate groups are expected to be present — increasing the potential for civil unrest at a gathering expected to draw thousands.

Northam, whose decision to temporarily ban firearms at the Capitol was met with resistance from gun rights groups, is trying to avoid the same deadly violence that marked an alt-right and white nationalist rally in Charlottesville in 2017.

The trio arrested this week face various federal charges, including transporting a machine gun and harboring an illegal alien. Their court-appointed attorneys could not be reached for comment Friday.

The FBI said during its surveillance, the men communicated about The Base, its activities and membership.

In the past, law enforcement, as well as anti-fascists and journalists, have managed to successfully monitor and infiltrate The Base, said Evan Balgord, the executive director of the Canadian Anti-Hate Network.

"After The Base arrests, some of these groups are saying on these public channels that they are shutting down recruitment," Balgord said. "They were spooked by the revelation in the affidavit that The Base was/is under significant surveillance."

That the FBI was able to gain access to the group and make these latest arrests would be reason enough for members to improve their online security, Balgord said, adding, "whether that means they don't recruit for a time, are more careful in their vetting, or move to another platform. That being said, it hasn't worked for them before."

Experts say the group uses encrypted chat rooms usually broken up into cells based on geographic location. They organize recruitment drives and make fairly sophisticated propaganda videos and posters.

Last November, members posted a 46-second video showing themselves placing recruitment posters around Boston University, The Associated Press reported. It was done in response to the Boston Anarchist Bookfair that was initially scheduled to be held on the university's campus; The Base called it a "communist gathering."

A sketch of a picture allegedly depicting The Base was shown on Jan. 16, 2020, in U.S. District Court in Greenbelt, Maryland. Bill Hennessy

Gipec, a cyber intelligence company that tracks online extremists, said Friday that it had been monitoring The Base's channel on the encrypted Telegram app for months and flagged the group's response to the arrests.

The post from Roman Wolf, believed to be a pseudonym for The Base's founder, described the arrests as "targeted harassment" and warned the group "will continue our struggle for survival undeterred."

It's a threat that law enforcement should continue to take seriously, said Brian Levin, director of the Center for the Study of Hate and Extremism at California State University San Bernardino.

"Having a network is a dangerous thing — particularity when there are folks with military or technical experience involved," Levin said.

With 2020 being an election year, he added, he expects the number of hate crimes to only increase. Over the past decade, his research has found that the two worst months for hate crime incidents in the U.S. were in November 2016 and October 2018.

"Groups like The Base are a symptom of a polarizing, fragmented society, but they're accelerated by it as well," Levin said. "While these sorts of groups have a short half-life once law enforcement comes after them, if you think this is the last we've heard from The Base or groups like it, you're sorely wrong."

At Holden's synagogue in northern Michigan, the anti-Semitic graffiti was power-washed off the building's sandstone walls following the incident. A New Jersey man was arrested on allegations of conspiring to vandalize the synagogue as well as a second one in Wisconsin.

According to a federal complaint filed in New Jersey, the suspect supplied the FBI with the names of fellow Base members whom he instructed to target the houses of worship. While the case remains ongoing, Holden said, he decided to get security cameras for Temple Jacob.

This year he also bought tourniquets and first aid gear — a purchase he never imagined having to make until now.

"These groups pose a real threat," Holden said, "not only to the people they target, but to civil society in general."