The corpse of a west London schoolgirl has turned up in the River Brent. Plainly this is grim news for the people who knew her, and the sympathies of the country are with them at this difficult time.

It’s important to get that out of the way, like the condolences handed out to the families of dead soldiers at the start of Prime Minister’s Questions, just before MPs start baying hateful abuse at each other and making noises that sound like a goat’s vinegar strokes. Now we’ve said that we feel distinctly sorry for the family of the dead girl, we can move on to the serious business of blame.

It appears the police think some Latvian did it. There’s a good chance he’s pissed off back to Latvia since the crime was committed – the very country in which a few years ago he murdered his wife in a forest. The word ‘lure’ is used when that tale is told. He sounds a bit of a git does Arnis Zalkalns.

If he did indeed kill the British schoolgirl, that makes the blame game nice and easy. We blame Zalkalns. I’m no criminologist but the world will be a saner place for all of us if the man who did the murder is the man blamed for the murder. But we can’t confirm that he did it yet, not least because nobody knows where he is except perhaps for a load of Latvians, and that’s where the art of blaming takes a fun turn.

He killed his wife and served seven years in prison for it. Not long enough, with hindsight, but he served his time, was released and as far as the Latvian authorities were concerned he was free to hot-foot it to Britain to mess with schoolgirls because of the EU’s rules on freedom of movement. He comes here, he’s arrested on suspicion of assaulting a different schoolgirl in 2009 and released without charge, and even has the gall to take a British builder’s job while he’s here, the bastard.

Something has to be done. The Latvians have let him go, not monitored him at all, he’s free to go where he wants in Europe and now he’s over here touching up and murdering our schoolgirls. Something is rotten at the heart of the European project when a man can come here from somewhere they speak a funny language and kill one of US, and piss off back east to blend in with the very people who’ve allowed this to happen.

That ‘something rotten’ is the way this story will highlight how we view ‘other people’. The implication is that, had Arnis Zalkalns stayed in Latvia and killed a Latvian schoolgirl, it would matter far less. Is that really where we’ve ended up?

We all know the media will latch onto a good child murder, particularly if it’s of a girl, ideally a white one, and if there’s a dodgy homemade video of her appearing in some shocking school play, all the better. It’s possibly a stretch to say the News of the World may have considered topping one or two nativity play Marys themselves when the phone hacking lost its lustre, but you get the point.

But if this young, pretty, white girl is foreign in some way, or killed somewhere else, that’s really not our concern. There’ll be a devastated family somewhere, but not here, so never mind. We like TV news shots of dull British streets with yellow police tape and small white tents like on Silent Witness, not mysterious overseas cities of dark rains and police uniforms we don’t recognise. If Latvians want to kill Latvians that’s their business. How dare they come here and kill US?

People frequently define themselves by where they’re ‘from’. I could lay claim to the area of London where I live, or claim to be a Londoner, or an Englishman, or British. Anything wider than that makes you out as a freak in 2014. Nonetheless, I’m a citizen of the EU, an inhabitant of the continent of Europe, an Earth-dweller and a member of the human race and why the bloody hell would I choose one of the mid-range classifications, British say, to decide whether I care about someone being murdered?

I never met Alice Gross and I don’t doubt she’s a huge loss for her family, but if she’d been Latvian, Albanian, Peruvian or someone on the International Space Station I’d care as much or as little. Now her body’s been found we’re about to embark on weeks of moaning about why the suspect was allowed to come to Britain to commit this crime, utterly ignoring that he could have gone to any other country and we probably wouldn’t have heard about it. But he came to Britain because ‘they’ all come to Britain, and if we can use the death of a schoolgirl to reduce the number of immigrants ‘coming over here, taking our jobs’, we’d be fools to miss the opportunity.

There’s just as much chance that a British fiend will travel to another European country and kill one of their schoolgirls, unencumbered by any form of monitoring by British authorities. Next time this happens, let’s see if there’s an outcry here about it. He could have stayed in Britain and killed someone here, but thanks to the freedom of movement he could happily head off to Banská Bystrica and commit the type of atrocity that makes Hostel look like The Best Exotic Marigold Hotel.

So as the shouting commences and lasts a full eight months to the election, consider taking a breath and defining yourself first and foremost as a human being who hates the nasty shit we do to each other, regardless of how close to home the victim might be. Alice Gross is a dead schoolgirl, and that’s awful. She’s not an excuse for xenophobia.