A former Ukrainian army officer will stand trial in Hamburg this week over the underwater explosions that crippled the Nord Stream gas pipelines in September 2022, in a case German prosecutors say could finally put sworn evidence on the record about one of Europe’s most politically charged acts of sabotage since the Second World War.
The Hanseatic Higher Regional Court is scheduled to begin hearings on Wednesday with Serhii K. in the dock. Privacy rules limit how defendants are named in German proceedings, but Italian extradition papers identified him as Serhii Kuznietsov, a Ukrainian citizen arrested last year while on holiday with his family in northern Italy.
What prosecutors allege
Federal prosecutors charge Serhii K. with causing an explosion and with a war crime — attacking civilian infrastructure — over blasts that ruptured Nord Stream 1 and damaged Nord Stream 2 on 26 September 2022. Gas bubbled to the surface of the Baltic for days, and the pipelines that once carried Russian gas to Germany have not returned to service.
In a summary of the indictment released ahead of the trial, prosecutors say Serhii K. and other military personnel developed a plan in late February 2022 “on behalf of state authorities in Ukraine” to halt gas deliveries and deny Moscow revenue from the trade. Investigators allege he entered Germany on a forged passport, helped place explosive charges on the seabed near Denmark’s Bornholm island, and detonated at least four charges weighing between 14 and 27 kilograms at depths of 70 to 80 metres.
Prosecutors have named seven Ukrainian suspects in the wider investigation, but only Serhii K. is in German custody. His defence team has said prosecutors have not offered direct, conclusive proof of his involvement and have signalled he will not testify about any military activities.
Why the courtroom matters now
Western governments initially pointed at Russia after the blasts, while Moscow blamed the United States and its allies. Anonymous briefings and leaked intelligence filled the gap for years. The Hamburg trial is the first time a structured case — with witnesses, documents and cross-examination — will test whether Ukrainian state actors ordered the attack.
That framing has already drawn sharp reactions in Kyiv. Ukrainian officials have not confirmed the German theory in public, and the war-crime classification has been criticised by some Ukrainian lawyers who argue the pipelines were legitimate military targets. Berlin’s government has largely stayed out of the pre-trial debate, stressing judicial independence.
What happens next
The court has listed twice-weekly sessions through at least February, with no firm end date. Prosecutors are expected to walk through travel records, communications and forensic work that tied the yacht Andromeda and its crew to the blast site. Defence lawyers are likely to challenge chain-of-custody issues and the leap from a small diving team to “state authorities.”
For Germany, the trial sits awkwardly beside efforts to keep Ukraine armed and united against Russia’s invasion. For Ukraine, any finding that senior officials signed off on an attack on energy infrastructure inside NATO’s neighbourhood could complicate diplomacy in Berlin and beyond. Serhii K.’s lawyers have said he is not authorised to discuss operational details even if he wanted to.
Whatever the verdict, the opening days in Hamburg will force governments that preferred quiet statements to confront evidence delivered under oath — and to explain how a single officer on trial came to personify a mystery that has shadowed European energy policy for four years.