Actually that's exactly how it works. You don't call the police directly like you're reporting robbery though. Your lawyers see a judge and file charges and obtain a warrant. THEN the police get involved and go to the defendant and gather evidence. Those extra steps are required, in theory, to make sure that a crime is likely taking place before the police get involved. At some point a judge approved this raid before it happened. The plaintiff presented evidence to support their claim, had their i's dotted and t's crossed, got the warrant, and in came the cops. That's sometimes how civil cases go.
Well as far as the Finnish laws go, the investigating police officer can issue a search warrant for anyone's home if there is "a reasonable suspicion". Whatever this "reasonable suspicion" can be, is up to anyone's guess. No need for a judge just yet. This procedure shows just how rotten a police state this country has become.