Police have finally arrested a suspect in the case of a student at the University of Freiburg who was raped, murdered, and thrown into the Dreisam river (g) on the 16th of October. News reports say that the clue came from a video surveillance camera which caught a man with an "unusual haircut and hair color" near the crime scene. Unconfirmed reports say that plainclothes cops rode the #1 streetcar looking for the haircut, and found it. More details to follow at an afternoon press conference.
Strange haircut and color, riding a purple women's bicycle? Are you thinking what I'm thinking?
Relax, it's a joke. But seriously, folks, it's obviously far too early to speculate. However, that's never stopped me before. I think the unusual haircut could be the shaved-sides long-on-top popular among certain spirited young lads, such as the ones on the left side of this picture:
Also, it seems a bit odd for a man to be riding a purple women's bicycle such as the one found at the crime scene. Unless, of course, he had no choice because the bicycle was donated (g).
From a policy perspective, this is another argument for video cameras. The typical Green argument against them is that even if they may help solve some crimes, they don't prevent crimes (g). This is the sort of argument they repeat like a shibboleth in front of like-minded audiences who nod in eager assent, but which withers when subjected to any scrutiny.
First and most obviously, why exactly is their role in helping solve crimes only mentioned in passing? People prefer living in societies where cops are able to solve crimes, and video surveillance is a reliable tool. The number of mistaken identity cases involving video surveillance is tiny, and vastly outweighed by the number of cases in which camera footage caught the right person. Cameras are certainly much more reliable than eyewitnesses.
Also, video cameras do prevent crime, as many studies have shown. Otherwise, insurance companies, generally not composed of idiots, would not encourage their use and advise on proper placement. The fact that we don't know exactly how much crime they prevent is the case of the impossible negative counterfactual: it's impossible to precisely measure things which do not occur. We know about how many cases of lung cancer were avoided by reductions in the smoking rate but will never know precisely how many for the same reason.
Second, video cameras prevent crime not only by deterring would-be offenders but by incapacitating the people who get caught. If the Freiburg Rapist turns out to be a serial killer, it is almost certain he will strike again. If he is caught and imprisoned for the rest of his life, he will never be able to do so. That means there will undoubtedly be several women who, unbeknownst to them, will owe their lives to this video recording and the police who found the killer with its help.
This is not an argument for cameras on every street corner, as you find in London. But it is an argument for evaluating the usefulness of cameras based not on abstract principle, but based on pragmatic, case-by-case evaluation.