A Mesa teen was arrested after making racially motivated threats online about carrying out a mass casualty incident, according to Mesa police spokesperson Detective Jesse Macias.
The FBI’s domestic terrorism unit had been monitoring the boy’s activity since late January after he made multiple statements online implying he was a resident in the Phoenix area, Macias said.
The FBI Phoenix’s field office was able to track down the teen and identify him as a student at Dobson High School, said Macias…