UNION, Ky. -- The man police said rammed his car into a crowd of people protesting a white supremacist rally was "very infatuated with the Nazis," according to one of his high school teachers.

James Alex Fields Jr. also wanted to join the Army but wasn't allowed to enlist because of his mental health history, the teacher said. The 20-year-old grew up in Union, Kentucky, and recently moved to Northwest Ohio.

Fields was arraigned Monday morning on a second-degree murder charge, as well as malicious wounding and failure to stop in an accident that resulted in death. He was denied bail.

Charlottesville police said Fields, rammed his Dodge sports car into a sedan, which then hit a minivan.

Video caught the Dodge reversing, hitting more people, its windshield splintered from the collision and bumper dragging on the pavement. Medics carried the injured, bloodied and crying, away as a police tank rolled down the street.

Warning: The video below contains language and images that may be disturbing to some viewers.

Heather Heyer was killed and 19 people were hurt.

The collisions sent the vehicles into a crowd of counter-demonstrators.

H.R. McMaster, President Donald Trump's national security adviser, said Saturday's violence "meets the definition of terrorism." Federal officials also have opened a civil rights investigation.

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His mother, Samantha Bloom, told The Associated Press on Saturday night that she knew her son was attending a rally in Virginia but didn’t know it was a white supremacist rally.

She said she'd told her son "to be careful" and to be peaceful.

"I thought it had something to do with Trump. Trump’s not a white supremacist," said Bloom, who became visibly upset as she learned of the injuries and deaths at the rally.

"He had an African-American friend so ...," she said before her voice trailed off. She added that she'd be surprised if her son’s views were that far right.

Bloom said they'd just relocated to the Toledo, Ohio area from Florence, Kentucky.

Derek Weimer, who taught two history courses to Fields at Randall K. Cooper High School in Union, Kentucky, said he was a quiet, respectful student but had some "radical ideas on race."

"He was very infatuated with the Nazis, with Adolf Hitler. He also had a huge military history, especially with German military history and World War II. But, he was pretty infatuated with that stuff.

"In his freshman year, he had an issue with that that was raised, and from then on we knew that he had those issues. I developed a good rapport with him and used that rapport to constantly try to steer him away from those beliefs to show clear examples -- why that thinking is wrong, why their beliefs were evil, you know, things like that," Weimer said.

He also recalled Fields wondering what society might be like if the Allies hadn't won.

"'What if Hitler had won? What if we had this large white supremacist empire going into the modern world?' -- that (Hitler's) views were right," Weimer said.

He said those views, combined with Fields' history of being prescribed antipsychotic medication, may have been a "perfect storm."

"I thought at times I got through to him," Weimer said, "but obviously not."

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Tanner Coleman, who knew Fields in passing at Cooper High, said he seemed like a "gentle giant" who was always alone.

"I seem to remember him being a very quiet guy who, when spoken to, was kind and shy," Coleman wrote in blog post Sunday.

Of the 19 patients taken to University of Virginia Medical Center, nine have been discharged and 10 are in good condition, Angela Taylor with UVA Health Systems told ABC News on Sunday afternoon. The hospital has treated additional patients related to Saturday’s events, Taylor said, but the facility does not have an exact number of patients.

The vehicle that hit the crowd was purchased in June 2015 from a car dealership in Florence, according to a Carfax report. The vehicle’s registration was renewed in Maumee, Ohio in 2016, the report said.

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The chaos boiled over at what is believed to be the largest group of white supremacists to come together in a decade: the governor declared a state of emergency, police dressed in riot gear ordered people out and helicopters circled overhead.

Oren Segal, who directs the Anti-Defamation League’s Center on Extremism, said multiple white power groups gathered in Charlottesville, including members of neo-Nazi organizations, racist skinheads and KKK factions. The white supremacist organizations Vanguard America and Identity Evropa; the Southern nationalist League of the South; the National Socialist Movement; the Traditionalist Workers Party; and the Fraternal Order of Alt Knights also were on hand, he said.

A photo from Segal shows Fields with Vanguard America, but the group denied he was a member.

James Alex Fields was w/ the Vanguard America folks in #Charlottesville. Learn more about the group > https://t.co/HNloF8Btnf @ADL_National pic.twitter.com/TmJLi0kfZo — Oren Segal (@orensegal) August 13, 2017

On the other side, anti-fascist demonstrators also gathered, but they generally aren’t organized like white supremacist factions, said Heidi Beirich of the Southern Poverty Law Center.

In addition to Fields, at least three more men were arrested in connection to the protests.

The Virginia State Police announced late Saturday that Troy Dunigan, a 21-year-old from Chattanooga, Tennessee, was charged with disorderly conduct; Jacob L. Smith, a 21-year-old from Louisa, Virginia, was charged with assault and battery; and James M. O’Brien, 44, of Gainesville, Florida, was charged with carrying a concealed handgun.

Just as the city seemed like to be quieting down, black smoke billowed out from the tree tops just outside of town as a Virginia State Police helicopter crashed into the woods.

Robby E. Noll, who lives in the county just outside Charlottesville, heard the helicopter sputtering.

"I turned my head to the sky. You could tell he was struggling to try to get control of it," he said.

He said pieces of the helicopter started to break off as it fell from the sky.

Both troopers onboard, Lt. H. Jay Cullen, 48, and Berke M.M. Bates, one day shy of his 41st birthday, were killed. Police said the helicopter had been deployed to the violent protests in the city, which has been caught in the middle of the nation’s culture wars since it decided earlier this year to remove a statue of Confederate Gen. Robert E. Lee, enshrined in bronze on horseback in the city's Emancipation Park.

In May, a torch-wielding group that included prominent white nationalist Richard Spencer gathered around the statue for a nighttime protest. That scene replayed Friday night, when white supremacists marched through the University of Virginia campus chanting "blood and soil," a Nazi slogan.

In July, about 50 members of a North Carolina-based KKK group traveled to Charlottesville for a rally.

Spencer returned for Saturday's protest, and denied all responsibility for the violence. He blamed the police.

Signer said the white supremacist groups who came into his city to spread hate "are on the losing side of history."

"Tomorrow will come and we will emerge," he said, "I can promise you, stronger than ever."

Four-hundred miles away, the mayor of Lexington, Kentucky, hinted that the white supremacists might get the opposite of what they’d hoped for. Mayor Jim Gray announced on Twitter that he would work to remove the Confederate monument at his county’s courthouse.

"Today’s events in Virginia remind us that we must bring our country together by condemning violence, white supremacists and Nazi hate groups," he wrote. "We cannot let them define our future."

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Associated Press writers Alan Suderman in Richmond, Virginia, Heidi Brown in Charlottesville, Claire Galofaro in Louisville, Kentucky, and John Seewer in Maumee, Ohio, contributed to this report.