You have to at least acknowledge that the police can "interview" people who can reasonably expected to have "knowledge" of a crime, even if they have no involvement.
You also have to acknowledge that immigration and citizenship violations ARE crimes. So the chief's position is indefensible even by his own BS standard.
Thats exactly what the article says, try rereading for comprehension. Just being arabic doesn't mean you are involved in a crime or have knowledge of a crime.
I'm not sure if th local police have jurisdiction in immigration affairs.