According to the article, only wikileaks was mentioned during the raid, police asked for passwords to the wikileaks.de domain, and police asked him to shut wikileaks.de down. So while there isn't much information available right now, the raid looks like it does not have to do with him running a Tor exit node.

I think it's based on a pervious article on HN a couple days back in which the author talked about how running a Tor exit node can get you arrested for downloading child porn. Nerd humor