Donaustahl head goes into hiding after warning of Russian threat
Stefan Thumann, founder and head of German drone manufacturer Donaustahl, has said that he has been living virtually underground for several months after German security forces warned him about an alleged operation by Russian special services against him. According to the entrepreneur, he fears for his life and is under heightened protection.
Thumann for the first time spoke in detail about his situation in an interview with Stern and RTL. According to him, shortly before Christmas 2025, German security authorities warned him about a Russian intelligence operation whose goal could have been his assassination. After that, the entrepreneur had to drastically change his lifestyle and give up many public appearances.
“I am effectively living underground,” — told the 39-year-old Thumann.
He also said that he had prepared a will, an organ donation order, and medical documents for emergencies. The location of the journalists’ meeting with the entrepreneur is not being disclosed for security reasons.
Suspects were watching the company head
The Federal Public Prosecutor General of Germany officially confirmed an investigation into people who may have been watching Thumann. In March 2026, law enforcement officers detained Ukrainian citizen Sergei N. and Romanian citizen Alla S. They are suspected of working for foreign intelligence.
According to the German prosecutor's office, since December 2025, Sergei N., on instructions from a Russian special service, had been collecting information about a person in Germany supplying drones and components for them to Ukraine. He studied information on the internet and filmed the target’s place of work. After his move to Spain, the surveillance, as the investigation claims, was continued by Alla S.
The prosecutor's office did not name Thumann in its March statement, but German media later identified him as the person under surveillance. Investigators believe that the collected information could have been intended for the preparation of further intelligence operations against the target. Sergei N. was detained in Spain and transferred to Germany in May, Alla S. was detained in the state of North Rhine-Westphalia.
Media reported a possible assassination plan
According to investigations by German media, security forces feared that the surveillance could have been part of the preparation for an assassination attempt. In an interview with RTL and Stern, Bundestag deputy Bastian Ernst said that the information he had indicated far-advanced preparation and the alleged use of the nerve agent “Novichok.” The official March statement from the federal prosecutor's office does not contain such details, so for now they remain assertions by sources and participants in the investigation, not a fact established by a court.
Thumann himself links the threat to his work for the defense industry and supplies of Donaustahl products to Ukraine. The company produces drone systems and components, and cooperation with the Ukrainian side, according to the entrepreneur, began to develop after the ILA air show in Berlin in 2024. Thumann claims that he already understood the possible risks at that time.
German security agencies in recent years have repeatedly warned about the growth of Russian intelligence and sabotage activity. The counterintelligence representative of North Rhine-Westphalia, Jürgen Kaiser, told Stern and RTL that one of the goals of such actions could be to intimidate heads of defense enterprises and try to force them to renounce support for Ukraine.
Based on materials from: Stern, Federal Public Prosecutor General of Germany
