[annalex]

Maybe there’s a connection to the Mexican cartels explaining the use of Spanish on the license plate and the name Diaz

Could be, but bizarre as it appears, Diaz/Dias is a known first name in Kazakhstan.

"Terrorista" is not really "use of Spanish"; it is an internationally recognized word and the suspect probably thought that the ending -a makes it sound more sinister, or funny, -- who knows. Or maybe "terrorist" was already taken. What is Obama's license plate?

[csvset]

Someone mentioned on a thread that terrosista #! was a character (?) or some such thing from a video game.

[HollyB]

I don’t think it was an official plate, just an front adornment style plate