Underwater explosions and gas leaks occurred on the Nord Stream 1 and Nord Stream 2 natural gas pipelines in 2022./Danish Defence Command/Forsvaret Ritzau Scanpix

Denmark has closed its investigation into the explosions on the two Nord Stream pipelines that occurred months into the start of the Ukraine conflict. The Danish authorities believe sabotage was involved, but after "complicated and extensive" enquiries said it would not proceed further. 

In a statement, Copenhagen police said "sabotage of the pipelines was intentional ...(but) there is not the necessary basis for pursuing a criminal case in Denmark."

It follows a similar announcement earlier in February by Sweden, who said the case did not fall within its own jurisdiction, instead transferring evidence gathered to German investigators.

'Huge methane peak'

Built and majority-owned by Russia's state-controlled Gazprom, Nord Stream 1 carries Russian gas from the Baltic port of Vyborg to Lubmin in northern Germany, and came into service in 2012. The second pipeline, completed in September 2021, has remained dormant since February 2022. 

Germany canceled certification, just days before the bombardment of Ukraine by Russian troops began. Seven months later, in September 2022, four ruptures were found on the two pipelines within the space of a few days. The authorities claim the leaks sent a "huge methane peak" into the Baltic Sea, off the Danish island of Bornholm.