The International Press Institute (IPI) today expressed concern over the extreme actions taken by Finnish police authorities following the release of a controversial article in the Helsingin Sanomat newspaper.

Police searched the Helsinki home of Helsingin Sanomat journalist Laura Halminen late on Sunday night. Halminen is one of two authors of an article on the signals intelligence facility of the Finnish defense forces that was published on Saturday.

The article, which referenced decade-old documents classified as “secret” and “top secret”, sparked an intense public discussion in Finland, with Finnish President Sauli Niinistö issuing a statement on Saturday citing concern about the damaging effects on national security of releasing highly classified information.

The National Bureau of Investigation (Keskusrikospoliisi) announced later that day that it had launched a criminal investigation into the article.  The case is being investigated as a “disclosure of national security secrets”, a crime punishable by four months to four years in prison.

According to the Helsingin Sanomat, police searched Halminen’s home from approximately 6:30 p.m. to 10:30 p.m. on Sunday, confiscating Halminen’s personal phone and a phone provided by the Helsingin Sanomat, as well as her computer, tablet and several memory sticks.

Halminen said that police did not provide evidence of any court order authorising the search.

Helsingin Sanomat Editor-in-Chief Kaius Niemi, a member of IPI’s Executive Committee, said that the search of a journalist’s home, especially on this scale, was “completely exceptional” in Finland.

“I view the implications of these events as deeply troubling for the conditions in which media operate, and for source protection,” he said.

On Sunday, following heated public debate, Niemi defended publication of the article, noting that changes to intelligence legislation proposed by the Finnish government could potentially increase the powers of intelligence officials and limit the public’s right to privacy. Among other changes, the proposed legislation would grant Finnish intelligence agencies more powers in monitoring online traffic.

Niemi emphasised that the paper, in publishing the story, was “carrying out its journalistic duty to inform the Finnish readership on the background to important events”. He maintained that the article did not contain information that could be seen as harmful to Finland’s national security.

IPI Executive Director Barbara Trionfi echoed Niemi’s concerns, saying that the use of classified sources of information in reporting is a legitimate journalistic practice, so long as it is justified by a clear public interest.

“The measures taken by the Finnish authorities over the article are disproportionate and of great concern in a country otherwise known for respecting press freedom,” she said.

“While national security issues are to be treated very seriously, going after journalists performing their duty informing the public on matters relating to civil liberties carries a chilling effect, which threatens to have negative consequences for journalism in the country. Even more so, considering that the sources in question were handled with proper care.”

Several editors in Finland voiced concerns about the incident’s impact on press freedom.

The editor-in-chief of the newspaper Kauppalehti, Arno Ahosniemi, said that in addition to the search of the journalist’s home, the criminal investigation itself was unheard of in Finland.

Riikka Venäläinen, the news editor of Finnish public broadcaster Yleisradio, called the case both exceptional and concerning.

“The latest turn of events is quite extreme, we are not used to this in a western society,” she said. It is cause for concern.”