The detainee, identified as Karsten L., “passed information he obtained in the course of his professional activities to Russia,” the federal prosecutor’s office said in a statement.
The suspect was arrested on Wednesday, but authorities searched his and another person’s place of work and residence.
“The investigation was conducted in close cooperation with the BND,” the statement said.
Bruno Kahl, chairman of the BND, said his agency would not comment on the matter at this time because “caution and discretion are very important”.
“In the case of Russia, we have a player whose lack of principles and willingness to use violence we have to deal with.”
“Every detail of this operation that becomes public means an advantage for this adversary in his efforts to harm Germany,” the BND head warned.
Since Russia launched a full-scale war against Ukraine in February, concerns about Moscow’s espionage activities in Germany have increased.
Last month, a German national was given a suspended sentence for passing information to Russian intelligence while he was a reserve officer in the German army.
In October, Germany’s cybersecurity chief Arne Schoenbom lost his job after a satirical TV show accused him of having ties to Russian intelligence.
At the same time, concerns have grown not only about Russian espionage activities, but also about attempts to sabotage critical infrastructure and cyber attacks.
Germany’s northern rail network was temporarily paralyzed in October due to sabotage, blamed by some on Russia.
Important communications cables were cut in two places and rail traffic was disrupted for three hours.
