At about 7 pm, the daily Dagens Nyheter published its report about indications of a type of "fake" mobile phone towers near government buildings that may make it possible to eavesdrop on the politicians and civil servants working in the area.
Shortly after that, Swedish Radio News reported about the investigation by the Post and Telecom Authority (PTS).
"We have been given indications that there could be illegal radio submitters, which is why we have started an investigation at the scene," PTS press officer Peter Ekstedt told Swedish Radio News.
"One enters the area with detecting equipment to try to find suspicious signals in the radio network," he said, as an explanation to what they were doing. The decision to do so came after contact between the PTS and the Swedish intelligence services on Wednesday.
Dagens Nyheter (DN) reports that it has found signs of so called IMSI-catchers (International Mobile Subscriber Identity) operating in the area. This is phone eavesdropping devices used for intercepting mobile phone traffic and tracking movement of mobile phone users. On Wikipedia, it is described as a "'fake' mobile tower acting between the target mobile phone(s) and the service provider's real towers".
Using an advanced encrypted phone known as Cryptophone, DN followed the example of the Norwegian newspaper Afterposten, which recently found a similar pattern in central Oslo. In Norway this has lead to a scandal, where politicians demanded an explanation from the intelligence services, after several fake mobile towers were found.
In Stockholm, during Tuesday and Wednesday, the Swedish daily's reporter registered 42 'suspicious activities' in the mobile phone network while walking in the area around the government buildings. This concerns cases where the mobile phone base station, a telephone mast to which mobile phones connect, does not behave as it usually does.
The Cryptophone found indications that instead of connecting to a normal phone mast, the phone was choosing a fake mobile tower, where in theory the phone calls, text messages and e-mails could be intercepted. The newspaper's reporter tried the phone in several places around the capital, and found that the area around the government building differed greatly from elsewhere, sounding the alert much more often over possible fake mobile towers.
When Dagens Nyheter contacted the Swedish intelligence services, Säpo, on Tuesday afternoon, the agency organised a meeting straight away. According to DN, at least one of the participants in the meeting was a manager of operations. In a statement to Swedish Television, the agency said the information from the paper was "interesting", but that there could be other explanations to the findings.