US: Ana Belen Montes (45) was the Pentagon's top expert on Cuba. But she strongly disapproved of US policies towards the island and so, for 16 years, she has also been Cuba's most effective secret agent yet exposed.
On Tuesday in a Washington court she pleaded guilty to conspiracy to commit espionage charges that will see her jailed for 25 years under a plea agreement reached with her lawyers.
Montes, a US citizen of Puerto Rican descent, who was only paid a small amount in expenses by the Cubans, was motivated by her belief "that US policy does not afford Cubans respect, tolerance and understanding", a statement read by her lawyer, Mr Plato Cacheris, said.
Among other secrets, she identified to Cuban intelligence four undercover US agents on the island - all safe - and gave Havana classified information relating to US national defence.
According to court papers, Montes communicated with the Cuban Intelligence Agency through encrypted messages and received her instructions over short-wave radio. From public pay phones, she then used a prepaid calling card to send coded numeric messages to a pager owned by Cuban intelligence.
The FBI secretly searched her home last May and uncovered coding data on water-soluble paper and information about several Defence Department issues, including a 1996 war games exercise conducted by the US Atlantic Command, authorities said. She was arrested following the attacks on September 11th, which heightened the need to "get her off the streets", a prosecutor said.
The highly secretive Defence Intelligence Agency, based at Bolling Air Force Base in Washington, where she worked as the senior Cuba analyst, provides analyses of foreign countries' military capabilities and troop strengths for Pentagon planners. She is believed to have been recruited by the Cubans in 1985 when she worked for the Freedom of Information Office and was encouraged to find work in the DIA.
Born on a US military base in Germany, Montes was raised in Kansas and Maryland and attended the University of Virginia. She got a Master's in international relations from Johns Hopkins in Washington DC. Friends say she was very discreet about her politics, which most thought conservative, and was regarded as an exceptional analyst.
Unlike other spies uncovered over the past years, such as the FBI's Robert Hanssen and the CIA's Aldrich Ames, Montes spied for ideological reasons, not money. Mr Cacheris is well known for his defence of Hanssen.