Finland's National Bureau of Investigation has started its investigations after several distributed denial of service attack (DDoS) attacks hit the OP-Pohjola financial group.
According to local news service YLE, police are now investigating the IT disruption which started on New Year's Eve and saw many users unable to access and use the company's online services up until today.
Investigators say that the company, the NBI and the Finnish Communications Regulatory Authority Ficora are now working together on the matter, which they believe can be traced to sources based in Finland and others abroad.
A group calling itself ‘CoreSec' has taken responsibility for the DDoS attacks, although Lizard Squad also highlighted the attack.
CoreSec posted to Pohjola's Facebook page on 31 December demanding 100 bitcoins (just over £30,000) to call off the attack and has previous form in this area; 18 months ago it carried out a DDoS extortion attack against Finnish pay-per-view (PPV) website Katsomo.
Although the group's motive hasn't been clear in the past, it is believed that this attack is in retaliation for the reported arrest of “Ryan” – a 17-year-old Finn who was said to have had a role in the Xbox Live and PlayStation Network outages on Christmas Day. Finnish police however insist that while the teenager was reprimanded on suspicion of committing “data crimes” he was not charged or arrested.
The Helsinki-based Pohjola is the largest financial services group in Finland and has four million customers in a country that holds just 5.4 million people.