The man who helped the San Bernadino muzzies get weapons was a Mexican muzzie convert who used his MX name; I think later it was revealed (IIRC) that he had a muzzie name too, could be wrong but not sure about that detail.
But he was Mexican (whether legal/illegal cannot remember) AND a muzzie convert. In the US, Hispanics have the largest number of muzzie converts.
Being muzzie and Mexican is not unusual; white, European ethnicity, black - muzzies come in every color, race, nationality.
It’s sad so many are converting, lj. The Catholic Church let many of them down when it diluted its message. Just the same way the Protestant religions let down African-Americans.
IIRC, The neighbor who sold him the guns was a childhood friend of the killer and they are also related by marriage.