A judge denied bail Monday to an Ohio man accused of slamming his car into a crowd of counter-protesters, killing one of them, during a white nationalist rally.

James Alex Fields Jr., 20, made his first court appearance — via video from jail — on charges of second-degree murder, three counts of malicious wounding and one count of hit and run.

Heather Heyer, 32, was killed and 19 people were injured on Saturday when a Dodge Challenger rear-ended a sedan, which then hit a minivan that had slowed to allow the counter-protesters to cross at an intersection, Charlottesville police said. The impact pushed the vehicles into the crowd, police said in a statement. The Challenger fled the scene, but officers stopped it a short time later and arrested Fields, police said.

Fields' mother Samantha Bloom told CBS News she heard about the charges facing her son from a news reporter.

"I just knew he was going to a rally," she told CBS. "I didn't know it was white supremacist. I thought it had something to do with Trump."

Derek Weimer, who taught Fields in social studies in high school in Union, Kentucky, told the Associated Press that Fields was fascinated with Nazism, idolized Adolf Hitler and had "deeply held, radical" convictions on race.

Weimer said Fields confided that he had been diagnosed with schizophrenia in his youth and had been prescribed anti-psychotic medication. Weimer described Fields as an "average" student deeply into military history and Nazi Germany.

"Once you talked to James for a while, you would start to see that sympathy towards Nazism, that idolization of Hitler, that belief in white supremacy," Weimer said. "It would start to creep out."