The investigation, led by German media and based on court documents and leaked records, revealed that technology was procured through a complex web of intermediaries, shell companies, and over 50 suppliers across Europe and beyond, often using legal loopholes.

A German court sentenced Russian businessman Alexander S. to nearly five years in prison for dealings with Mostrello and related entities, highlighting ongoing clandestine procurement activities.

Western companies, knowingly or unknowingly, have contributed to Russia’s military buildup by supplying critical technology, exposing gaps in export controls and sanctions enforcement.

An international investigation has uncovered a covert Russian effort to bolster its nuclear deterrent in the Arctic by deploying an advanced underwater surveillance system called 'Harmonie,' designed to detect Western submarines and protect nuclear assets.

This secret network, spanning thousands of kilometers of cables, sensors, and sonars, is aimed at monitoring NATO submarine activity and safeguarding Russia’s strategic nuclear sites in the Barents Sea.

Central to this operation is Mostrello Commercial Limited, a Cyprus-based company owned by a Moscow businessman, which procured critical underwater technology and ships—some of which were transferred to Russia, including former German vessels.

German authorities identified Mostrello as a front for the project, and a trader named Alexander Shnyakin was convicted for coordinating dual-use technology sales, though he denies knowingly reselling to Russia.

In 2024, U.S. and European authorities targeted the network, sanctioning Mostrello and its key figures for supplying Russia with military and nuclear-related technology in violation of export controls.

European firms such as Norddeutsche Seekabelwerke and Innomar supplied cables and sonar equipment worth over $50 million, often without knowledge of their military applications.

The equipment involved includes advanced military technologies, raising concerns about the effectiveness of European export restrictions on sensitive items.

Despite strict sanctions, Russia has continued to import military technology post-2014 and after the 2022 invasion of Ukraine, using shell companies and legal loopholes to circumvent restrictions.

Leaked financial records and court documents show Russia's persistent efforts to acquire underwater surveillance technology, with transactions passing through multiple countries and involving complex networks.