It may be parallel construction, but in a kind of cynical way we can publicly praise it as good traditional police work. It takes credibility away from demands for special or clandestine access.
When we call it parallel construction we buy into the surveillance communities marketing... that surveillance it is effective.
I suppose that if you have one administrator in a cell, it's probable that you will get the login credentials after a while.
The question is how to put them in a cell to begin with, but I don't think that it requires some super high tech or shady wiretapping. The publicly known lawful interception laws are most likely good enough for finding almost anyone accessing a know site.
As the current situation is in regards to islamistic terrorism in Europe, I really expect the law to be used to its full extent.
Unfortunately, the harsh stand on drugs play both criminal organizations and islamists in hand as they can make good money on even relatively harmless drugs. I'd prefer a legalization and regulation on those, in order to decapitate the black market.
When we call it parallel construction we buy into the surveillance communities marketing... that surveillance it is effective.