London, Nov.17 : An Estonian defence ministry official, who was arrested in September, could have passed on secrets on the US missile shield and cyber-defence to Russian Intelligence, while working with NATO.
Herman Simm, 61, is being accused of handling all of his country's classified information at NATO, giving him access to every top-secret graded document from other alliance countries.
He was recruited by the Russians in the late 1980s and has been charged in Estonia with supplying information to a foreign power, reports The Times.
Several investigation teams from both the EU and NATO, under the supervision of a US officer, have flown to the Estonian capital Tallinn to assess the scope of what is being seen as the most serious case of espionage against NATO since the end of the Cold War.
On the face of it, the Simm case resembles the old-fashioned Cold War spy story. He used a converted radio transmitter to set up meetings with his contact, apparently someone posing as a Spanish businessman.
As in the 1950s and 1960s, it seems that the operation was a husband-and-wife team. His wife Heete - who previously worked as a lawyer at the national police headquarters - has also been detained on charges of being an accessory to treason.
Simm was ensnared because of blunders that have dogged modern espionage ever since the KGB first pitted itself against the West. Second, his contact officer got careless and tried to recruit a second agent - who reported the incident to the security authorities.
That is when the Estonian mole-hunters began to reconstruct the movements of the supposed Spaniard and followed the thread back to the agent inside NATO.