"An extensive preliminary investigation has been underway since the attack. Sweden has collaborated with several other countries in attempts to identify and locate the individuals behind the crime, but the evidence that has emerged is not sufficient to pursue the investigation further," said preliminary investigation leader Sandra Helgadottir in a press release.
Data on just over 1.5 million people was leaked when Miljödata was subjected to a cyberattack in the fall of 2025. The data was published on the darknet.
The preliminary investigation may be resumed if new leads emerge, according to the Prosecution Authority.
On August 23, a cyberattack was carried out against the system supplier Miljödata, which counts 80 percent of municipalities among its customers.
Regions, authorities and private organizations also use Miljödata's system for handling, among other things, labor law matters, rehabilitation matters and handling work-related injuries and incidents.
The group behind the cyberattack gained access to data on just over 1.5 million people.
This includes, for example, social security numbers, telephone numbers, residential addresses, email addresses, employment IDs, as well as profession and position.
On September 14, the data was published on the darknet.
The incident was investigated as a serious data breach and attempted aggravated extortion.
