Using documents leaked by National Security Agency whistleblower Edward Snowden, Der Spiegel reports that the NSA has turned Germany into its most important base of operations in Europe. "NSA is more active in Germany than anywhere else in Europe," reports the paper, "And data collected here may have helped kill suspected terrorists."

The German archive provides the basis for a critical discussion on the necessity and limits of secret service work as well as on the protection of privacy in the age of digital communication. The documents complement the debate over a trans-Atlantic relationship that has been severely damaged by the NSA affair.

They paint a picture of an all-powerful American intelligence agency that has developed an increasingly intimate relationship with Germany over the past 13 years while massively expanding its presence. No other country in Europe plays host to a secret NSA surveillance architecture comparable to the one in Germany. It is a web of sites defined as much by a thirst for total control as by the desire for security. In 2007, the NSA claimed to have at least a dozen active collection sites in Germany.

The documents indicate that the NSA uses its German sites to search for a potential target by analyzing a "Pattern of Life," in the words of one Snowden file. And one classified report suggests that information collected in Germany is used for the "capture or kill" of alleged terrorists.