Sweden's chief prosecutor on security issues, Tomas Lindstrand, "has decided to launch a preliminary investigation of illegal intelligence activities. The probe regards American actions to protect the US mission in Stockholm and American personnel," his office said in a statement.
The announcement came two days after Swedish Justice Minister Beatrice Ask announced that the US embassy in Stockholm had secretly spied on Swedish residents in the capital since 2000.
“It’s my responsibility to launch a preliminary investigation into whether there is reason to believe a crime has been committed,” Lindstrand told the TT news agency.
“It’s appropriate to investigate whether a crime was committed and in this one has to be thorough.”
Lindstrand refused to comment on how long his investigation may take, saying simply that he aims to determine "on one hand, if a crime has been committed, and on the other who has committed the crime, if it has been committed," Monday's statement said.
Lindstrand will conduct the probe with the assistance of Swedish security service Säpo, his office said, adding that the case was classified and no further
information would be released for the time being.
According to Gothenburg University law professor Dennis Töllborg, the crime most likely to be the subject of the investigation is that of conducting unauthorised intelligence activities.
“Unauthorised intelligence activities is likely to be what we’re talking about here. That’s if someone, in secret or though ‘deceptive measures’, collects information about someone else’s personal situation for a foreign power,” he told TT.
A spokesperson for the US embassy in Stockholm welcomed the Lindstrand's decision to open a probe into the programme.
"The embassy is very open about this programme and we’re very willing to cooperate with the prosecutor’s office in any way we can," US embassy deputy press attaché Ryan Koch told The Local following the prosecutor's announcement.
"We understand Swedish concerns and are trying to be as open as we can so we can clear up any misunderstandings."
On Sunday, both Säpo and the Swedish government refused to comment on whether they knew about the surveillance activities carried out by the US embassy's Surveillance Detection Unit (SBU), which came to light on Saturday.
However, a centrally placed person who worked in the Swedish Government Offices (Regeringskansliet) during a large part of the the last decade told the Svenska Dagbladet (SvD) newspaper on Sunday that Säpo are likely to know about the US surveillance activities "because Säpo keeps track of all the embassies, including the American one."
"I am not particularly surprised that this happens," the source told SvD.
Anders Thornberg, head of Säpo's department for security measures, added is too early to say whether the surveillance carried out by the US embassy is illegal.
"What Säpo currently knows is that above all else, the investigations were conducted with the aim of protecting the US embassy and other places in Stockholm where the embassy carries out activities. The information has since been collected and sent on to the US," Säpo wrote in a statement on Monday.
According to Säpo, the US embassy did not inform the justice or foreign affairs ministries about the information gathering activities.
Neither did it inform Säpo or the police about the activities carried out under the programme, which has been in place since 2000.
Late on Saturday, the US embassy in Stockholm admitted that it, like other US embassies, has a programme to detect suspicious activities around its facilities as part of normal security precautions to ensure the safety of staff and guests, but challenged the initial claims made in Norway.
On Wednesday, Norway's TV2 reported that the US embassy in Oslo had conducted illegal surveillance on hundreds of Norwegian residents over the past decade. Similar allegations were aired a day later by a Danish commercial broadcaster.
Talking earlier in the day with TT, the US embassy's Koch claimed on Monday that the programme was carried out in cooperation with domestic agencies.
“When the Surveillance Detection Unit programme started at the end of the 1990s, we were instructed to cooperate with local authories. We’ve done so, we’re doing so, and we’ll continue to do so in the future,” he said.
When asked about claims that the Swedish justice ministry and Säpo didn’t know about the programme, Koch hinted at a possible communication breakdown within the Swedish bureaucracy.
“We’ve always cooperated with local authorities and the cooperation was worked very well. But I don’t know how they report onwards up the chain,” he said.
Koch regretted the confusion generated around the programme which he claimed does exactly what its name describes – identify people who are watching the US embassy in order to reduce possible threats.
“We know that there are those in Sweden who monitor us who have bad intentions. Sweden isn’t immune to threats,” he said.
However, Koch refused to answer questions about where the embassy’s SDU activities take place.
“I can’t comment on the details of how the activities are carried out. But it’s sort of like the neighbourhood watch programmes that exist in both Sweden and the United States – you keep an eye on people who aren’t usually in the neighbourhood,” Koch told TT.
Nor would he reveal details about specific methods used in the programme.
“I can’t comment other than to say that we take all threats against the embassy seriously,” he said, deferring other questions to the US State Department in Washington.
Left Party leader Lars Ohly also reported the government to the Riksdag’s constitutional committee, citing the United States’ collecting and registering information about Swedish citizens.
“We have to get to the bottom of this. If there has been cooperation between Swedish and foreign agencies to carry out surveillance without having been sanctioned by the government, it’s a crime against our basic rights and freedoms,” Ohly said in a statement.
He wants the Riksdag’s constitutional committee (Konstitutionsutskott – KU) to look into whether Swedish agencies helped with the surveillance and data registration. He also wants to know if any government representatives gave their consent to the activities.