Overview
- German investigators, citing reporting by Die Zeit, say they uncovered surveillance of Stefan Thumann, founder of drone maker Donaustahl, after a foreign intelligence tip led to an inquiry that began in December 2025.
- Authorities first detained a man identified as Sergey N. in December 2025 but released him for lack of evidence and later found phone data suggesting contacts with Russian intelligence and surveillance of Thumann and his father.
- Prosecutors say two suspects, Sergey N. and a Romanian woman named Alla S., were arrested and are held in pretrial custody on alleged clandestine agent activity following a March round of detentions and a later extradition from Spain.
- Official arrest warrants cite espionage‑style agent activity rather than an attempted‑murder charge, and Thumann is reported to be under heightened personal protection while the Bayerisches Landeskriminalamt continues its probe.
- Security services and the Kanzleramt have repeatedly discussed the case, which officials view as part of a wider pattern of Russian hybrid tactics that could put other German defence firms and managers at risk and may prompt tighter protection and intelligence cooperation.