David: it's true we could do massively interesting researches once we will have this system for some years!
But I agree that abuse will be so easily, not only from the 'government side' (people who work there) but also at the criminal side indeed. That would be really messy

But still, it seems like such a good initiative so see who was at the place the crime happened.. And wouldn't there be additional test to see if it's not fake DNA, or someone left it there on purpose?
I agree the findings of DNA should not be sufficient to lock someone up, but it can lead you to people who maybe know something (witnesses too for example).
I still don't have a strong opionin in favour or against a DNA database...