The 20-year-old James Reardon Jr. was apprehended after posting on his Instagram account a video of himself firing a weapon with a caption which read: "Police identified the Youngstown Jewish Family Community shooter as local white nationalist Seamus O'Rearedon."
The name “Seamus” is a Gaelic version of the name “James.” He is being held on telecommunications harassment and aggravated menacing charges.
The Youngstown Jewish Family Community tagged in the post by the suspect is located some 21 km (13 miles) from the village of New Middletown where the 20-year-old lived and was arrested.
The social media post - published on July 11 - prompted the local police to launch an investigation and later contact the FBI.
Upon closer examination of Reardon’s Instagram, the police found various anti-Semitic and white nationalist content, including racial slurs and rants about minorities.
The FBI Violent Crimes Task Force then raided the suspect’s house, seizing dozens of rounds of ammunition, several semi-automatic weapons, a gas mask, bulletproof armor as well as anti-Semitic propaganda.
Reardon was also later identified as one of the people interviewed in a National Geographic documentary about the infamous Unite the Right Rally in Charlottesville, Virginia on August 12, 2017. The marchers chanted anti-Semitic slogans, while carrying Nazi flags and neo-Nazi symbols.
New Middletown is located some 105 km (65 miles) from the city of Pittsburgh, Pennsylvania where a gunman shot dead 11 people at a Tree of Life synagogue on October 27, 2018.