Hi,
http://www.wired.com/2014/08/operation_torpedo/
"Operation Torpedo began with an investigation in the Netherlands in
August 2011. Agents at the National High Tech Crime Unit of the
Netherlands’ national police force had decided to crack down on online
child porn, according to an FBI affidavit. To that end, they wrote a web
crawler that scoured the Dark Net, collecting all the Tor onion
addresses it could find.
The NHTCU agents systematically visited each of the sites and made a
list of those dedicated to child pornography. Then, armed with a search
warrant from the Court of Rotterdam, the agents set out to determine
where the sites were located.
That, in theory, is a daunting task—Tor hidden services mask their
locations behind layers of routing. But when the agents got to a site
called “Pedoboard,” they discovered that the owner had foolishly left
the administrative account open with no password. They logged in and
began poking around, eventually finding the server’s real Internet IP
address in Bellevue, Nebraska."
The operation is in known in the Netherlands by the name of Descartes.
The name "Torpedo" was their internal nickname for the operation. The
case was a followup to the Robert M.-case, one of the largest child
abuse-cases in the Netherlands.