James Reardon Jr., 20, has been charged with telecommunications harassment and aggravated menacing and is being held in the Mahoning County Jail on $250,000 bond with a court hearing planned for Monday morning.
On Friday, the FBI Violent Crimes Task Force raided Reardon's house and seized a cache of weapons and ammunition, including dozens of round of ammo, multiple semi-automatic weapons, a gas mask and bulletproof armor.
"Grateful for the work of the FBI, local law enforcement and our community partners in the Youngstown Jewish community. We will continue to employ all our resources to stop the spread of white nationalism and violent extremism," the Anti-Defamation League in Cleveland tweeted.
Grateful for the work of the FBI, local law enforcement and our community partners in the Youngstown Jewish community. We will continue to employ all our resources to stop the spread of white nationalism and violent extremism.https://t.co/T4pcDHSRI6— ADL Cleveland (@ADL_Cleveland) August 18, 2019
Police initially became aware of Reardon on July 11 when he posted a video on Instagram of a man shooting a semi-automatic rifle with sirens and screams in the background. He tagged the Jewish Community Center of Youngstown in the post.
"That kicked off an intense investigation, a very rapidly evolving investigation, because of the way the world is," New Middletown Police Chief Vince D'Egidio told Youngstown ABC affiliate WYTV.
Reardon is an avowed anti-Semite and white nationalist and attended the deadly "Unite the Right" rally in Charlottesville, Virginia, in 2017, according to WYTV. During the raid on his house on Friday police also discovered anti-Semitic and white nationalist propaganda.
Extra security was given to the community during the police investigation, which will remain in place for the near future, police said. But even though the active threat has ceased, there is still active concern among some in the community.
"I'm confident that we are doing what we need to do at this point, but the world has changed and we always have to assess what we are doing moving forward," said Andrew Lipkin, from the Youngstown Area Jewish Federation.
A man killed 11 people when he opened fire on a synagogue in Pittsburgh, only an hour southeast of Youngstown, last October.
Reardon had publicly stated before that he wanted to see a homeland established for white people when he was interviewed for a documentary, according to D'Egidio. Police also discovered that his social media feed was filled with racial slurs and derogatory statements about minorities.
"This is a person that has declared himself as a white nationalist. With the hate crimes and everything else going on, we want to make sure we do our part to make sure this person was taken off the streets very quickly," D'Egidio said.
The FBI has not yet announced whether they will pursue federal charges against Reardon.
ABC News' Ahmad Hemingway contributed to this report.