One thought here (and slight thread creep).

I note the high profile and very public instances where an innocent man has been incarcerated as a result of faulty evidence etc. but what of all the cases where the right man has been brought to book?

Please don't tell me that the prisons are full of innocent men, all there because the system did not work properly. Those are the ones that, generally, don't get publicised because they aren't dramatic enough and don't provide for the bread and circuses mentality that the media seems to want to feed these days.

Against those wrongly accused think of those like Sutcliffe, Timothy West, Harold Shipman, Ian Brady, Denis Nilsen - the list goes on.

I would think that, against the pressure to find the culprit nowadays, there must be a mounting pressure to get the right man, if only to avoid the scandals that will surely ensue as a result of a faulty arrest. While that authorities may desperately want to be able to chalk up a successful arrest if they are not certain that they have their man they risk leaving the real culprit free to commit further crimes and that ain't going to make them look very good the next time a woman turns up murdered, is it?