Russian intelligence services were reportedly preparing an assassination attempt against Stefan Thumann, the head of German defense startup Donaustahl, which supplies reconnaissance and kamikaze drones to Ukraine, Die Zeit reports. A document from the country’s Federal Office for the Protection of the Constitution describes the case as an alleged planned assassination — one so significant that, according to the outlet, it is regularly discussed at weekly intelligence briefings in the Federal Chancellor’s Office.
In December 2025, a man named Sergei N. approached Thumann’s home in the Lower Bavarian town of Strasskirchen, filming the building’s entrance on his phone and photographing the nameplate listing its residents. German intelligence had received a tip from their foreign counterparts indicating that Thumann presented an elevated threat risk.
Bavarian police detained Sergei N. and seized his phones, but they failed to decrypt the data during the period in which they could keep him in custody. Only later was it established that he had been in contact with Russian intelligence officers — and that he had also attempted to surveil Thumann’s father to determine the son’s whereabouts. By that point, Sergei N. had already left for Spain with his family, but surveillance of the younger Thumann was continued by Romanian national Alla S., who lived in North Rhine-Westphalia.
Both were detained in March 2026 — Sergei in Spain, and Alla in Germany. Neither was a career intelligence officer. Instead, investigators consider them to be “disposable agents” — vulnerable individuals recruited online. The actual assassination, according to investigators, was to be carried out by other operatives. The Federal Court of Justice judge did not include the murder plot theory in the arrest warrant, which only cites suspicion of espionage activity.
Thumann founded Donaustahl in 2019, and since 2023, the company has been manufacturing drones. He speaks publicly and forcefully about Russia, writing on his LinkedIn page:
“Russia does not want peace. It wants to destroy the West.”
The entrepreneur is currently under heightened security protection and hints that attending public events has become dangerous for him, telling his followers that “for certain reasons” he is unable to attend trade shows.
Additionally, according to Die Zeit, another defense company is on the radar of Russian intelligence, and investigators cannot rule out the possibility that its director’s life is also at risk (though further details remain classified). Notably, on June 11, Serbian border guards stopped a truck at the Serbian-Hungarian border that was carrying explosives in concealed compartments. The drivers’ phones contained contacts with Russian intelligence officers, and the truck’s destination was Bavaria, where Quantum Systems and Helsing operate, alongside Donaustahl. A court in the Serbian city of Subotica confirmed to Die Zeit that suspects Danilo B. and Slobodan D. are in pretrial detention.
BILD had previously reported on the detention of two alleged “disposable agents” carrying an explosive device at the Serbian-Hungarian border. As early as 2024, reports emerged that Russian agents had been surveilling Rheinmetall CEO Armin Papperger, and Berlin operates on the assumption that such assignments could not have been made without the Kremlin’s approval.
