This photo provided by Charlottesville, Va., authorities shows James Fields Jr., who on Thursday had the most serious charge against him upgraded to first-degree murder in the death of a woman at a Unite the Right rally.

The man who police say intentionally rammed his car into a crowd of counterprotesters at a white nationalist rally in Charlottesville, Va., this summer, now faces a first-degree murder charge. A judge upgraded the second-degree murder charge against James Fields Jr. at a preliminary hearing on Thursday.

The 20-year-old Ohio man has been in jail since his arrest on Aug. 12, when police say he accelerated into a group of people, killing Heather Heyer and injuring some three dozen others.

The incident was part of a deadly weekend in Charlottesville that began as a purported protest against the removal of the Robert E. Lee statue and spun into a national controversy. On Friday night, white supremacists marched across the University of Virginia campus with torches and chants of "Jews will not replace us," and wound up brawling with counterprotesters.

The next day, Unite the Right, a white nationalist demonstration, brought hundreds of demonstrators and counterprotesters to downtown Charlottesville. Among them was Heyer, 32, who friends say always spoke up against racism and anything that she felt was wrong.

Fields, from Maumee, Ohio, was there too.

"Investigators want to know whether Fields crossed state lines with the intent to commit violence," NPR's Carrie Johnson has reported.

Some who knew Fields say he had a long fascination with Nazi Germany. He was "deeply into Adolf Hitler and white supremacy," a former high school teacher told member station WVXU.

Prosecutors now will take the case against Fields to a grand jury and ask for an indictment.

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