- Published
Serhii K appeared relaxed as he checked in to the glamping resort near Italy's Adriatic coast with his wife and young children.
Dressed in shorts, sandals and a dark baseball cap, the former Ukrainian Special Forces soldier strolled back and forth, chatting with the receptionist and dipping repeatedly into a bowl of free snacks.
asserted
soldier → publish → snacks
But German police were already closing in on him.
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police → close → him
After a painstaking investigation, they had concluded that Serhii K had commanded Europe's biggest act of sabotage in decades: a series of explosions in September 2022 deep beneath the Baltic Sea that ripped through the giant Nord Stream pipelines and ruptured the supply of Russian gas to Germany.
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that → conclude → Germany
Next week, following his extradition to Germany and months in isolation in a high security prison, Serhii K will go on trial in Hamburg.
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K → follow → Hamburg
He is charged with causing an explosion and a war crime – attacking civilian infrastructure – allegedly acting on behalf of "state agencies of Ukraine".
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He → charge → Ukraine
Both he and his country have denied any involvement.
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he → deny → involvement
Under Germany's privacy rules, he will be named during the trial only as Serhii K, but during extradition proceedings he was identified as Serhii Kuznetsov.
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he → name → Kuznetsov
It was 02:03 am on 26 September 2022 when the first blast severed part of the Nord Stream pipelines, sending vast quantities of gas gushing through the surface of the Baltic Sea.
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quantities → sever → Sea
There were two further explosions targeting both Nord Stream 2 – not yet in action, but already full – and the original Nord Stream 1 that had supplied around half of Germany's annual demand for natural gas.
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that → be → gas
Prosecutors say "high-performance explosives" were planted approximately 80m (260ft) below the surface: four devices weighing up to 27kg each, activated with timers.
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explosives → say → timers
They "strongly suspect" that Serhii K led a crew that included four deep-sea divers, using a rented yacht called Andromeda.
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that → suspect → yacht
Once their complex, dangerous mission was done, the saboteurs slipped back into Ukraine unaware of the DNA evidence some had allegedly left on the boat.
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some → do → boat
As word of the blasts spread, experts and some governments initially rushed to the same conclusion: they blamed Moscow.
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they → spread → Moscow
Russia had a history of hybrid attacks, after all, and of using its energy supplies for political pressure.
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Russia → have → pressure
But as the airwaves filled with commentators citing "suspicious" Russian naval activity near the blast site, German police ignored the noise.
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police → fill → noise
They went on following the forensic crumbs.
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They → go → crumbs
Eventually they led to Ukraine.
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they → lead → Ukraine
The case since built by investigators alleges that Serhii K entered Germany for the Nord Stream attack on a forged passport, likely issued by Ukraine's security services.
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K → build → services
In the extradition files sent to Italy he is named as Serhii Kulinich.
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he → send → Kulinich
That might explain why he looked so calm on his holiday in Italy.
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he → explain → Italy
He had been travelling widely, and without incident, for the past year.
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He → travel → year
In a copy of his real passport seen by the BBC there are more than two dozen stamps from countries including France, Spain and Canada – all dated after the Nord Stream attacks.
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all → see → attacks
But by 13 August 2025, Germany had identified its key suspect and this time, when Serhii K crossed into Poland, he was detected.
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he → identify → Poland
Italian police say the actual arrest warrant was only issued on 18 August after he had travelled south and left Poland, suggesting the Germans were not sure their neighbours would co-operate and detain him.
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neighbours → say → him
By the time his wife made a booking at La Pescaccia though, he was officially a "wanted" man.
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he → make → Pescaccia
As soon as he showed his passport at check-in at the resort, the local carabinieri got an automatic alert.
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carabinieri → show → alert
Police arrived to make their arrest late that night, leading Serhii K away from the glamping site and his family in handcuffs.
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Police → arrive → handcuffs
The saboteurs
None of the Nord Stream suspects have spoken publicly and no-one admits any role in the explosions.
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one → speak → explosions
But I have talked to some of the Ukrainians caught up in the case, and people close to them.
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I → talk → them
"Anyone who admits involvement in this mission, they're immediately a target for Russia," one source explained.
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source → admit → Russia
"Whoever did it can never confirm that.
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Whoever → confirm → that
But it also made Germany and others dependent, giving Russia immense leverage over Europe.
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Germany → make → Europe
That is why Ukraine, the US and Poland in particular all loathed it.
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Ukraine → loathe → it
Another source I spoke to was "eaten alive by anxiety" over the investigation and baffled that Germany, a close ally of Ukraine, was even pursuing prosecution.
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Germany → speak → prosecution
"Many Ukrainians believe that these pipelines, they helped Russia to fight so blowing them up was a good thing for our country," they pointed out.
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they → believe → country
The German prosecutor's office told me the justice system was outside of any politics.
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system → tell → politics
Equally frustrating for the Ukrainians I met was their own government's silence.
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silence → meet → Ukrainians
"At the very minimum, he's a military man, so if there are any questions, they should be addressed to the state, not to him," a close contact of Serhii K complained.
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contact → be → K
Ahead of his extradition to Germany, his lawyer here in Italy told me his client had felt "abandoned".
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client → tell → me
Germany has a whole list of suspects, but only one other name has been revealed so far.
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name → have → suspects
…and 26 more, not listed.
The Aporia
