A German citizen was arrested at the Munich airport on suspicion of treason for allegedly colluding with an intelligence service employee to pass on intelligence to Russia, the prosecutor general's office said on Thursday.
The man, identified as Arthur E., was arrested on Sunday upon arriving in Germany from the United States, the prosecutor said in a statement. He is said to be an associate of Carsten L., an employee of the German foreign intelligence service (BND) who was arrested in December on suspicion of spying for Russia.
Arthur E., who is not a German intelligence employee, is believed to have passed on to the Russian intelligence service information he had obtained from Carten L., according to the prosecutor's statement.
An arrest warrant had already been issued for Arthur E., who was brought before a judge of Germany's top criminal court on Monday and remanded in custody, the statement added.
The investigation was conducted it close cooperation with the BND and the U.S. Federal Bureau of Investigation (FBI), the prosecutor said.
German authorities have warned of likely heightened Russian spying given the Kremlin's stand-off with the West over the Russian invasion of Ukraine.