Was there a mentor in the shadows goading him on, only to slink back into anonymity after the deed was done?
Might not have needed a mentor to goad him on, he may have watched some recent news online- all those European terror attacks using vehicles, and got the idea from that.
It’s not unusual for the bigoted white types to be antisemitic as well, and sympathetic of muslim terrorists. McVeigh was sympathetic with Iraq’s leader Saddam...
One white group took Saddam up on a paid trip to Iraq to put on a street theater show there.
So it’s possible the guy got the idea from observing muslim terrorists.