Prosecutors identified the man only as trained scuba diver Vladimir Z, however he is understood to be Volodymyr Zhuravlyov, who was arrested in Poland in 2025 over the undersea plot.
In that case, a Polish judge refused a German extradition request, arguing that if Ukraine was responsible for the attack, then it was a “just” act.
Zhuravlyov was then released, prompting a ripple of surprise from the crowd in court and a smile from the man in the dock.
The other suspect in the case is former Ukrainian military officer Serhiy Kuznetsov. He was arrested in Italy in August 2025 and later extradited to Germany where he is set to face trial. He has denied responsibility for the explosions and appeared before a court in Hamburg in June.
Prosecutors allege Kuznetsov led a team that used a yacht rented at Rostock in Germany to plant explosives on the pipelines close to the Danish Baltic Sea island of Bornholm.
In a letter sent to the United Nations Security Council following the explosions, and reported by Reuters at the time, German investigators said “traces of subsea explosives were found in the samples taken from the boat”.
Although the Nord Stream 1 pipeline was in operation at the time, Nord Stream 2 had yet to go into service.
After Zhuravlyov’s planned extradition from Croatia, officials said he will be brought before an investigating judge to face charges of causing explosions and sabotage.
Blame for the blasts, which crippled a long-controversial energy supply line from Russia to Germany, initially focused on Moscow until signs of Ukrainian involvement began to emerge.
Officials in Kyiv have repeatedly denied any role.