The deal seems harmless. In December 2020, as shipowner Jan Nempel recalls, he was approached by Russian businessman Alexei S., who was interested in the former research vessel “MV Aquarius Dignitus”. After several inspections, the Russian's company bought the ship for 2.3 million euros, ARD reports.
“Everything seemed serious to us”, Nempel told German public media. The Russian said that he would use the ship to conduct research for a large Russian raw materials company.
“Aquarius” is just one of many research and special vessels bought by Alexei S.'s company from the West over the years. And not only that: through his Cypriot company “Mostrello” and other companies, Alexey S. also bought the most advanced technologies: underwater robots, special sonars and underwater cables. The investigation has also established what all this was for.
The secret military project "Harmony"
For more than ten years, Russia has been acquiring leading technologies from EU countries such as Germany, the USA, Japan and Canada in order to build an underwater reconnaissance system in the Arctic to protect its nuclear weapons. This was established within the framework of the investigations of the international project “Russian Secrets”, in which the German media NDR, WDR and “Süddeutsche Zeitung” also participate.
Based on financial and court documents, as well as information from the security services, these studies reveal for the first time the scale of the network of companies through which Russian businessmen purchased equipment in the West. It becomes clear that at least until 2024, Russian companies imported goods and many ships from ten European countries, the USA, Japan and Canada.
“Harmony” is an underwater sensor system that can detect Western submarines. Its purpose is to protect Russia's strategically important arsenal of nuclear weapons in the Arctic.
Western intelligence agencies consider the project extremely sensitive, also because tensions in the Arctic are rising and Russia has significantly increased its military capabilities in Murmansk and the Kola Peninsula in recent years.
The location is strategically advantageous for Russia, because from there both the United States and Europe can be quickly reached by missiles. After Russia's invasion of Ukraine and the renewal of Russia's nuclear doctrine last year, Western security services see an increase in the threat posed by Russian nuclear capabilities.
The system is installed in the Barents Sea
„Harmony" strengthens Russia's ability to detect Western submarines and thus ensure the unhindered and undetectable movement of its own nuclear submarines, said Brian Clark of the Hudson Institute in Washington, quoted by ARD. Clark is a former senior US naval officer who also served on a submarine.
„This is an attempt by Russia to limit the US's ability to reach areas around submarine bases and monitor them." The US first installed an underwater reconnaissance system in the 1950s to be able to react to possible attacks. Britain has just announced that it is also building such a system, German public media reported.
The studies made have made it possible to identify the likely location of the secret underwater system „Harmony" - the traces lead to the Barents Sea, where it, probably in the form of a bow, is located in the waters off Murmansk, Novaya Zemlya and Alexandra Land.
Under US sanctions since 2024
At the center of the Russian network that provided the equipment is businessman Alexei S. with his company „Mostrello". In the past, his companies have repeatedly worked for the Russian military and Russian intelligence.
According to publicly available documents, one of the central Russian companies in the network has signed a contract with the arms concern „Kometa". It is assumed that it was he who built „Harmony", but all questions on the subject addressed to the Russian government and „Mostrello" have remained unanswered.
„Mostrello" and a number of related companies have received sensitive underwater equipment and research vessels worth more than $50 million since 2013, according to journalistic investigations. The equipment was taken to Russia and at least some of it was used for “Harmony”. In 2024, the company was eventually sanctioned by the United States.
No violations
The information suggests that „Mostrello", among other things, acquired equipment from the state-controlled arms concern „Kongsberg" in Norway in 2015. The British company „Forum Energy Technologies Ltd." was ordered a „Mohican" type underwater robot in 2014, which can operate at depths of up to 3,000 meters. „Kongsberg" states that they acted lawfully and did not commit any violations of the law. „Forum Energy Technologies Ltd." did not answer the questions asked.
The studies do not reveal any evidence that the companies were aware that their equipment could be used in Russia for military purposes. This also applies to the German companies that appear in the documents, such as a shipyard in Bremen, which provided two vessels. A company official confirmed the sale and assured that all legal requirements were met.
Sales for “civil purposes"
According to the investigation, the German cable factory NSW in Nordenham received about $15 million from deals with “Mostrello" between 2013 and 2019 - such as for telecommunications cables. A spokesman for NSW's parent company - Prysmian from Milan - said that the German factory only sold standard cables for civil purposes and fully complied with the legislation.
The documents also show that the company Innomar GmbH from Rostock delivered a special sonar to “Mostrello" in 2015. It was installed on a Russian ship, but, as the company claims, exports are carefully examined in advance, and there were no restrictions on the sonar in question.
Sentence for violating sanctions
Since 2014, the EU has repeatedly tightened export rules for Russia, and they have been particularly strict since the invasion of Ukraine in 2022. But deliveries continued after February 2022 - including from a cargo company from Germany. In September 2025, a Kyrgyz-Russian businessman was sentenced to almost five years in prison for doing business with “Mostrello” and thus violating EU sanctions.
The indictment states that “Mostrello” provided equipment to supply “Harmony” with electricity and to provide capabilities for sending signals. This was established by the CIA.
The EU sanctions officer David O'Sullivan explained in an interview with ARD that Russia had found “extremely sophisticated and clever ways to circumvent sanctions”. Therefore, O'Sullivan appeals to the Community countries and companies to try to prevent this type of supply system that circumvents the rules. "We must work just as smartly and decisively to prevent this as the Russians are working to achieve it," he says.
Authors: Antonius Kempmann, Katharina Buss, Sven Lohmann, Merlin Menze, Alice Pesavento, Lea Struckmeier, Benedikt Strunz (NDR), Petra Blum, Florian Flade (WDR), Manuel Bewarder (WDR/NDR)