If the cops put out an alert for a Hispanic, or a black person I'm pretty sure you'd be able to identify them. Is it genetically scientific? Of course not! But other people will also categorise that person the same way, thus allowing their "racial" group to be targeted. Race might be a bullshit term, but we clearly assign people to such groups so it's just as valid as any other construction we've come up with (like the difference between a Canadian and an American).
You can be black and Hispanic. And my favorite...according to the federal government, it is entirely possible to be "Hispanic - White and Black."
At which point we can all agree that discussions of race are almost always more confusing than helpful.
¯\_(ツ)_/¯
Source: worked on some USDA reports.