Polish police have arrested a Ukrainian national, identified as diver Volodymyr Z, on suspicion of involvement in the 2022 Nord Stream pipeline explosions.

German prosecutors allege he was part of a group that planted explosives on the Nord Stream 1 and 2 pipelines, participating directly in the dives.

He faces charges of sabotage and causing explosions, but his lawyer says he will challenge extradition to Germany, arguing the case is inadmissible because Gazprom—the pipeline owner—funds Russia’s war in Ukraine.

Another Ukrainian suspect, Serhii K, was detained in Italy last month and is fighting extradition.

Investigators believe the group used the yacht Andromeda, rented with forged documents, to carry out the operation near Bornholm, Denmark. Germany has identified seven suspects, including former Kyiv diving school members, though one has died, the BBC has reported.

Sweden and Denmark closed their own probes earlier this year without naming suspects, and no evidence has emerged linking Ukraine, Russia, or any state directly to the blasts.