Säpo in November refused Birgitta Almgren, a researcher at Södertörn University south of Stockholm, access to the lists of Swedish contacts for Communist East Germany's (GDR) Stasi secret police.
The Administrative Court of Appeal (Kammarrätten) upheld Säpo's decision when it rejected Almgren's appeal in February.
Professor Almgren has now taken her case to Sweden's highest administrative court arguing that as the GDR and the Stasi ceased to exist 20 years ago the documents can no longer reasonably be argued to pose a threat to international relations or Sweden's national security.
"Access to the documents requested is essential for research into Sweden during the Cold War and, in a wider perspective, to show how dictatorships work and how an open, democratic country can be systematically infiltrated," Almgren writes in her submission to the court.
Almgren hopes that the documents will support her hypothesis that the GDR considered Sweden to be a "focus country" in its foreign policy and functioned as a bridge between East and West in the Cold War.
She furthermore argues that her research is more of an archiving nature and she has no intention to sensationalise the issue or expose names of those contained in the lists.
This is the second time that Birgitta Almgren has pushed the case to the Supreme Adminstrative court after her leave to appeal an Administrative Court of Appeal decision from October 2007 was rejected in December 2007.
The documents that Almgren is seeking access to form part of the so-called Rosenholz files or "Stasi lists" which ended up in the hands of the CIA during the German reunification, but were finally returned to Germany and their respective countries in 2003. The files contain details of informal contacts that the GDR had in a slew of countries.
The German parts of the Rosenholz files are open for public viewing at the Stasi archive in Berlin but the Swedish files remain classified.
In an article in the Svenska Dagbladet daily on February 22nd, Säpo's head of information Åsa Hedin claimed that there was no such "Stasi list", arguing that the approximately 50 Swedish names that featured in the Stasi files found after the fall of the Berlin wall have been fully investigated by the security police.
"In most cases, it appeared that the criminal charges were completely baseless. The people in question had never had access to any secret information and knew no one who had access to classified material," Hedin wrote.
Hedin argued that that espionage crimes committed by the small number of Swedes recruited as agents by the Stasi had already exceeded the statute of limitations by the time their names had been made known to Säpo.
The decision to deny access to the files was defended "partly on national security grounds, partly in the interests of our organization and partly out of consideration to the individuals," the Säpo spokesperson explained.
The Local has made attempts to contact Birgitta Almgren on Tuesday and Wednesday but without success.