It was 2 a.m. on September 26, 2022, when seismic monitoring stations in Denmark, Sweden and Germany registered a weak earth tremor.

At the same time, workers at the pipeline operator Nord Stream registered a sharp drop in pressure in the 1,200-kilometer (745-mile) gas pipes that connect Russia and Germany. As the sun rose over the Baltic Sea, giant bubbles of methane gas could be seen from the air near the Danish island of Bornholm. They were coming to the surface from about 80 meters (260 feet) underwater. Further tremors followed. Soon it became clear: Several sections of the Nord Stream 1 and 2 pipelines had been blown up.

A key component of German and European energy infrastructure had been destroyed.

Investigations yield nothing substantial

It is here that the trail of officially confirmed findings runs cold. Instead, a vast realm of conjecture, speculation and suspicion has opened. Straight after the attack, many pointed the finger at Moscow. Ukrainian presidential adviser Mykhailo Podolyak wrote on Twitter, today known as X: "'Gas leak' from NS-1 is nothing more that [than] a terrorist attack planned by Russia and an act of aggression towards EU." 

Reactions from officials were sharp: "Any deliberate disruption of active European energy infrastructure is unacceptable & will lead to the strongest possible response," European Commission President Ursula von der Leyen wrote on the same platform after meeting with Danish Prime Minister Mette Frederiksen following the attack.

A year after the undersea explosions, it has not yet been officially confirmed who was behind the attacks on the gas pipelines. Investigations are underway in Germany, Sweden and Denmark, but very little information has been made public. Increasingly, attention is turning toward what investigative journalists are publishing.

In March 2023, a German investigative team caused a stir when it published research pointing towards Ukraine. The 15-meter yacht "Andromeda" played a key role. According to the collaborative investigation by stations of the German public service broadcaster ARD and Die Zeit newspaper, five men and one woman set sail on the boat from the Baltic Sea port of Warnemünde, in Germany, on September 6, 2022, about three weeks before the pipeline attack. Investigators from the German Federal Police Office (BKA) were reported to have found traces of explosives on board the yacht — the same substance that had been detected on the bottom of the Baltic.

Ukrainian special operations forces?

In early June, a report appeared in the Washington Post media outlet which supported this version of events. It claimed that European and American secret services had already been warned about plans for an attack by Ukrainian divers on the Nord Stream pipeline in June 2022. According to the Washington Post, the special operations forces reported directly to the commander-in-chief of the Ukrainian armed forces, General Valery Zaluzhny. Ukrainian President Volodymyr Zelenskyy, however, was not informed about the plans.

In late August, following an extensive investigation, a 20-person investigative team from German news magazine Spiegel and public broadcaster ZDF also concluded: "The clues point in one direction: toward Ukraine." Wolf-Wiedmann-Schmidt was one of the members of the team. The journalist told DW: "The investigators found nothing which could prove that Russia could be behind it, and even less which suggested that the US could be behind the attack. There is absolutely no evidence of that."

In February, a widely published report by acclaimed American journalist Seymour Hersh accused the US of initiating the explosion. Hersh had based his report on a single, anonymous source.

US threats against Nord Stream

In any case, Hersh could point to statements made by US President Joe Biden during his inaugural visit from German Chancellor Olaf Scholz in early February 2022, before Russia launched its all-out invasion of Ukraine. At that time, Biden said in front of the gathered press: "If Russia invades ... then there will no longer be Nord Stream 2. We will bring an end to it."

A few days after the attack, US Secretary of State Antony Blinken said that the Nord Stream explosions offered "a tremendous opportunity to once and for all remove the dependence on Russian energy."

The German-Russian energy partnership had been a thorn in the side of the US long before the war in Ukraine — as well as for Ukraine and other European countries. Washington had long sought to prevent the construction of Nord Stream 2, a pipeline that ran parallel to its predecessor and was completed in September 2021, and used sanctions to delay it considerably. The second pipeline was never put into use, as the German government blocked approval shortly before Russia's invasion of Ukraine.

Russian motives

Russia also had a motive to destroy the gas pipes: Because the Russian company Gazprom had already stopped the flow of gas through Nord Stream 1 in the summer of 2022 – and in doing so violated its contractually assured delivery obligations. That would have opened the door to recourse claims from its Western partners. The destruction of the pipeline allowed Gazprom to invoke "force majeure" — rendering the recourse claims invalid. This theory, however, assumes that Russia would abide by the rulings of international courts.

A war crime according to international law

According to international law, the attack on the Nord Stream pipeline would be an illegal act, even in the context of a military conflict, Bonn-based international law expert Stefan Talmon told DW. "That is because the Nord Stream pipeline is a civilian infrastructure project. According to the Rome Statute of the International Criminal Court, destroying civilian infrastructure is not only a violation of international law, but a war crime."

At least it would be if one of the two countries at war, Russia or Ukraine, could be proven to be behind the attack. If a third country had blown up the gas pipeline, the law professor explained, "that would not come within the framework of the law of armed conflict, instead it would ultimately be a terrorist attack." Talmon is critical of possible claims for compensation because of so-called state immunity: "Before a national court, Russia as well as Ukraine or a third country could invoke this state immunity, as it also applies for such unlawful attacks."

It remains to be seen whether the perpetrator will ever be identified, and if so, whether the case of the Nord Stream explosions will ever have its day in court. If a trial were to be held, Chancellor Olaf Scholz wants it to take place in Germany.

This article was originally written in German.

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