German authorities thwart Russian intelligence plot targeting drone supplier for Ukraine
German intelligence services have thwarted an alleged assassination attempt targeting Stefan Thumann, the head of Donaustahl-a defense company that supplies reconnaissance and combat drones to Ukraine. Authorities believe Russian intelligence agencies may have been behind the plot, according to German newspaper Die Zeit .
Court documents reveal that in December 2025, a man named Sergey N. arrived in the town of Straßkirchen, Bavaria. He was seen photographing Thumann’s home and gathering information about the company executive. German security officials soon identified this activity as part of a potential assassination plan, sparking a series of closed-door meetings between law enforcement and government officials to discuss the threat.
Investigators believe Thumann may not have been the sole target. Russian intelligence services reportedly showed interest in at least one other executive from another German defense firm, whose identity remains undisclosed. Details about the case have been classified.
This isn’t the first time Russian operatives have been linked to surveillance of German defense leaders. In 2024, Russian intelligence agents were caught trailing Armin Papperger, CEO of Rheinmetall. German officials say such operations could not have been conducted without the Kremlin’s approval.
Donaustahl has supplied drones to Ukraine’s defense forces since 2023. Thumann has been an outspoken supporter of Kyiv and a vocal critic of Russian aggression.
The threat to Thumann was first uncovered by a foreign intelligence service, prompting German authorities to quickly detain the Russian agent conducting the surveillance. He was briefly held but soon released, and subsequent investigations confirmed his connections to Russian intelligence. However, by then, he had already escaped from Germany to Spain with his family.
In the spring of 2026, Spanish authorities detained Sergey N., and in Germany, Romanian citizen Alla S. was also arrested under suspicion of surveilling Thumann. Both now face charges related to operating on behalf of a foreign intelligence agency.
Following the discovery of the assassination plot, Thumann’s personal security was significantly increased.
In a related incident, a truck was stopped at the Serbian-Hungarian border at the height of the investigation. Authorities discovered a hidden cache of explosives inside. Contact information for Russian intelligence was found on the detainees’ phones. The truck’s destination was Bavaria-the same region where Thumann lives and where several major German defense companies are based.
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