James Alex Fields Jr., second from left, at a white supremacist rally. He allegedly later drove a car into a crowd of counterprotesters, killing one person and injuring many more. Vanguard America, a white supremacist group with whom Fields congregated, denies that he was a member. (Alan Goffinski/AP)

James Alex Fields Jr. held up a black shield emblazoned with Vanguard America’s logo, and he stood shoulder-to-shoulder with members of the self-proclaimed fascist group as they formed a barrier around a statue of Gen. Robert E. Lee. At the white nationalist rally in Charlottesville on Saturday, Fields also sported the unofficial uniform of the group: a white polo shirt and khaki pants.

Soon after, Fields allegedly drove a car into a crowd of counterprotesters, killing a 32-year-old woman and injuring at least 19 people. Vanguard America was quick to say Fields was not a member of the group and had nothing to do with the contingent at the rally. He had simply walked up and grabbed a shield — which he displayed upside down, as shown in photos — and stood a post with Vanguard.

“The driver of the vehicle that hit counter protesters today was, in no way, a member of Vanguard America,” the group said in a statement on Twitter. “The shields seen do not denote membership, nor does the white shirt. The shields were freely handed out to anyone in attendance.”

The secretive organization has been emerging publicly since the presidential election, starting with white nationalist fliers on several college campuses and recruiting on a website that vilifies Jews, racial minorities, gays and multiculturalism. Group members have been rallying alongside neo-Nazis, white nationalists and white supremacists, and its members have been seen in images on social media — faces often blurred — as groups of young white men waving black flags and wearing black hats emblazoned with a Vanguard America white eagle logo.

Men who say they are members of the Vanguard America organization pose in Washington’s Lafayette Square on May 12. They declined to give their names or show their faces. (Ricky Carioti/The Washington Post)

Despite the group’s presence at numerous white nationalist rallies, the most notable being the Charlottesville event, it is unclear how many members Vanguard America has or what broader influence it has achieved. The group’s website rails against the loss of white control of the United States and proclaims white America’s “right to exist.”

Leaders claim to have more than 100 members nationwide, many of them in the Washington region and in Texas, but they have declined The Washington Post’s requests for reporters to attend membership meetings. Five men who said they are members of Vanguard met with Post reporters on the Mall this year; all wore masks and some wore sunglasses. They almost always speak anonymously.

Dillon Irizarry, 29, a Marine veteran who served in Iraq and Afghanistan and identifies himself as the group’s president, said in a Skype interview Monday that his is a political group that does not call for or condone violence. He said that Fields has nothing to do with Vanguard, which says it has strict membership criteria, including that applicants be employed, not smoke or drink, or display hand or neck tattoos. Irizarry legally changed his name to Dillon Ulysses Hopper in 2006 and served in the military using that name, according to court and military records.

A spokesman for Irizarry said no one using Fields’s name ever applied to join Vanguard: “I can assure you if he did apply, by his actions, he seems psychotic. He would not have gotten in.”

Fields obtained the Vanguard shield in Charlottesville because of a “communications error,” the spokesman said. Vanguard equipment was distributed to “any person who asked” or “who showed up.”

The Vanguard leader who made the decision to distribute shields to nonmembers — including Fields — is now being drummed out of the organization, Irizarry said. “The reason this person was photographed with us was due to leadership being incompetent,” Irizarry said.

While arguing that counterprotesters were responsible for some of the violence Saturday, Irizarry and his spokesman condemned the vehicle attack.

“Personally, I’m disgusted,” the spokesman said. “We obviously do not condone violence. We don’t tell our members to do this kind of stuff. We are a political movement . . . nothing more.”

The group’s manifesto states that it is not an advocate of lawlessness and does not condone or endorse the use of criminal activity. It also says that members “who wish to commit criminal acts are expelled, and those left are those who assuredly respect the law.”

By distancing itself from Fields, Vanguard acknowledged that white nationalist movements are attracting unaffiliated people — many of them young men — whose motives range from political demonstration to hatred to violence. And because much of the recruitment for the rallies is done online, it can draw anyone from anywhere. In this case, Fields drove from Ohio and was able to blend in immediately.

Oren Segal, director of the Anti-Defamation League’s Center on Extremism, said Vanguard America is “loosely organized and not particularly coherent.” Much of its organizing targets 18- to 24-year-olds, he said.

Segal, who tweeted a New York Daily News photo showing Fields at the rally, said whether he was an official Vanguard America member is in some ways irrelevant.

“You have this individual dressed like a white supremacist, holding a white supremacist symbol and hanging out with white supremacists,” he said. “Whether he was a member or not, that was his crew for that day.”

Irizarry, whom the ADL also identifies as the group’s leader, said Vanguard has a centralized application procedure. Its website — removed from its host Monday and republished on another host as of Tuesday morning — lists requirements, saying members must be “at least 80% White/European heritage,” and that the group prohibits “homosexuals, transsexual, adulterers, or any other form of sexual degeneracy,” as well as criminals and those with addictions.

Vanguard makes clear that it is a white nationalist group that seeks “a nation for our people.”

“A multicultural nation is no nation at all, but a collection of smaller ethnic nations ruled over by an overbearing tyrannical state,” the group says on its website. “Our America is to be a nation exclusively for the White American peoples who out of the barren hills, empty plains, and vast mountains forged the most powerful nation to ever have existed. Vanguard America stands indomitably opposed to the tyranny of globalism and capitalism, a system under which nations are stripped of their heritage and their people are turned into nothing more than units of cheap, expendable labor.”

But members say they do not want to appear as neo-Nazis. They want respect.

“ ‘Fascist’ is an accurate term,” said a man who identified himself as Francisco Rivera, speaking in front of the White House in May. Rivera, who said he is a spokesman for Vanguard America’s Virginia branch, also appeared at an anti-sharia rally in Harrisburg, Pa., in June, giving a speech to about a dozen people there. “The lying press and the feeble politicians preach at us that we need more multiculturalism,” Rivera said. “To them we say . . . we will take action to defend our country.”

The Southern Poverty Law Center, which tracks hate groups, said in May that its information on Vanguard America was sketchy. Heidi Beirich, director of the SPLC’s Intelligence Project, said that Vanguard America does not have a membership list.

“There has been a bit of a sea change in the white supremacist world in the last few years,” Beirich said. She said that five or six years ago, she thought that the movement was dying but that it has since been infused with a new generation of adherents.

Julie Tate contributed to this report.