Uh-huh. Would the "authority" making this statement be one David Gonzalez, U.S. Marshall for the District of Arizona?
Or possibly his assistant, one Fidencio Rivera, Deputy U.S. Marshall for the District of Arizona, prominent member of the Latino Peace Officers Association (what one might call a "Hispanic Supremacy Group").
The murderers in question may belong to some prison biker gangs that are identified as "white supremacist", but the prisons segment that way (black/brown/white gangs) and it's ludicrous to identify them as anything but a bunch of thug garbage.
Funny how the reporters covering this story had almost immediate access to the “expert opinion” of the Southern Poverty Law Center, huh?