They apparently passed the papers to staff from the Russian consulate general in Bonn via so-called "dead-letter boxes", and communicated with Moscow via satellite phone and by leaving comments on YouTube videos.
Andreas, 51, and Heidrun, 46, moved to West Germany in the late 1980s when Putin was a key KGB officer in the East German city of Dresden. Prosecutors have not ruled out the possibility that the couple worked with Putin when they embarked on their alleged spying career. Both had false Austrian passports - Anschlag's claimed he was born in Argentina, his wife's that she was born in Peru. German intelligence officers are reported to have remarked at Andreas Anschlag's thick Russian accent.
Andreas studied engineering and plastics technology and held down a number of jobs in the German car parts industry before he and his wife were arrested.
There have been suggestions the Germans were tipped off by Alexander Poteyev, an ex-Russian intelligence officer who is believed to have told the FBI about the Russian spy ring involving the agent Anna Chapman which operated in the US until its members were arrested in 2010.
Investigators reportedly found the Anschlags as a direct result of information obtained from interrogating the Chapman ring.
- Independent