I agree it could be a key piece of circumstantial evidence if they have other circumstantial evidence to tie him either to the crime scene or the crime itself.
But by itself, I think it is hardly damning seeing we know he lived not far away.
Such is the nature of circumstantial evidence. It is the cumulative nature which is important.
So far all we really have is a bunch of propensity reasoning.
We know he did a rape of a 72 year old woman. We know he had child *advertiser censored*. We know he was a drug dealer. We know he committed crimes like burglary.
But to me, none of this reaches the standard required of admissible similar fact evidence.
We have nothing to say he abducted a child before, or attacked a child.
We have nothing to say he murdered anyone before.
Maybe the germans have this evidence, but until I hear of it, I remain sceptical.