Swedish prosecutors said on Friday they would conduct a new supplementary crime scene investigation into the Nord Stream leaks, after the navy and pipeline owner also began investigations this week.

“I have decided to carry out a series of supplementary inspections of the crime scene together with the Security Service (Sapo),” prosecutor Mats Ljungqvist said in a statement.

The Swedish Armed Forces have decided to assist the investigations upon request, Ljungqvist added, without giving details of what they are looking for.

Four leaks occurred in the two Nord Stream pipelines in the Baltic Sea off the Danish island of Bornholm at the end of September. Seismic institutes reported registering two underwater explosions before the leaks occurred.

While the leaks were in international waters, two of them were in the Danish exclusive economic zone and two of them were in Sweden.

At the beginning of October, the Swedish public prosecutor’s office announced that it had collected “evidence” during an underwater inspection of the leaks in the Swedish economic zone, which had substantiated the suspicion of sabotage.

The new inspection comes as the Swedish Navy and the pipeline’s owner, Nord Stream AG, both announced earlier this week that they would conduct their own inspections of the ruptured pipelines.

Jimmie Adamsson, chief of communications for the Swedish Navy, confirmed that they were on site with a vessel specializing in diving operations and were supporting the new prosecutor’s inspection.

However, he stressed that this is not related to the poll they initiated themselves this week.

“The first investigation didn’t trigger the second, but they’re two different things,” Adamsson told AFP.

Nord Stream AG, majority-owned by Russia’s Gazprom, said Thursday that a “specially equipped vessel” arrived at the site of the “pipeline damage in Sweden’s exclusive economic zone.”

The pipelines linking Russia to Germany were at the center of geopolitical tensions as Russia cut off gas supplies to Europe in alleged retaliation for Western sanctions over Moscow’s invasion of Ukraine.

Although they were not operating when the leaks occurred, they both still contained gas that was seeping through the water into the atmosphere.