German prosecutors have searched a home as part of an investigation into the sabotaging of Russian-controlled gas pipelines.
The search was linked to a theory suggesting operatives with connections to Ukraine were behind underwater explosions that knocked the Nord Stream pipelines out of action.
Local broadcasters said a potential witness, believed to be a partner of a Ukrainian suspect, was interviewed and had her phone seized at her home near the Polish border.
The woman had DNA samples taken to compare them to those found on a yacht at the centre of the investigation, according to reports.
Leaks from the German investigation have suggested the yacht Andromeda could have been used by divers to reach the Nord Stream pipelines or as a decoy.
Federal prosecutors also confirmed they had searched the home of a woman who was not a suspect.
The explosions affected the Nord Stream 1 and 2 pipelines in September last year, seven months after Russia’s invasion of Ukraine.
The blasts, in Danish and Swedish waters, were picked up by seismic monitors before coast guards saw leaked gas bubbling to the surface of the Baltic Sea.
Nord Stream theories
Several theories have circulated as investigators in Germany, Sweden and Denmark try to unravel the underwater explosions.
Ukrainian officials have denied involvement amid speculation that a “pro-Ukrainian group” may have sabotaged the pipelines that were built to carry gas from Russia to Europe.
Kyiv had lobbied against the opening of Nord Stream 2 on the grounds that it would circumvent Ukrainian transit routes and tighten Moscow’s economic hold over the continent.
US officials dismissed suggested claims from Moscow that it was behind the high-risk act of sabotage.
Another theory suggested that Russia carried out the attacks to permanently cut off gas supplies and send a warning to western infrastructure.
The Danish military reported in April that it had spotted a Russian submarine rescue ship in the Baltic a few days before the blasts.
The Kremlin branded claims that their own forces blew up pipelines to a major revenue stream as “stupid”.
Neither pipeline was functioning at the time of the explosions, after Russian exporter Gazprom cut off gas through Nord Stream 1 in August.
German Chancellor Olaf Scholz suspended the Nord Stream 2 project shortly before Russia’s invasion, with the pipeline never going into operation.
