Not only was this guy arrested, the article at the link shows a woman was arrested for technically and actually, transporting explosives and she corresponded with Dylan Roof. The article does not make it clear if the two cases are related. I don't see it off-hand.
Excerpting a somewhat lengthy article:
Ohio Man Arrested for Plotting Terror Attack Against Toledo Synagogue
By Zachary Stieber
December 11, 2018 Updated: December 11, 2018
An Ohio man arrested for plotting a terror attack on a synagogue told investigators that he was inspired by both the terror group ISIS and the recent mass shooting at a Pittsburgh synagogue.
Damon Joseph, 21, was charged on Dec. 10, with one count of attempting to provide material support to the ISIS, the Department of Justice said.
...
Toledo Woman Arrested
The Department of Justice also on Monday announced the arrest of a Toledo woman after she bought black powder and screws that she thought would be used to make a bomb, which would then be used in a terror attack.
Read more at: https://www.theepochtimes.com/ohio-man-arrested-for-plotting-terror-attack-against-toledo-synagogue_2735562.html
The woman? A Neo-Nazi or something? Off her rocker. Pictures of the accused at link.
My opinion, these kids are getting brainwashed off of what else could be doing it? The internet. We didn't have this stuff going on.