"[I]n no other NATO member state are Russian spies caught as often. The Estonian Internal Security Service (Kaitsepolitseiamet – KaPo) is an intelligence service considered one of the best and most resistant to Russian infiltration in the former Eastern Bloc. The Russians themselves admit this, as the Estonian service has for years been one of their most difficult opponents in Europe."
"Estonians do not hush up nor minimize the cases of detained and deported Russian spies. In the annual report on state security (“Aastaraamat”) issued since 1998, the Kaitsepolitsei exposes Russia’s operating methods, naming people and organizations (and showing photos) of those suspected of contacts with Russian intelligence. This detailed report on the operation of the agency was the first publication of its kind in the world. The fact that Estonia has one of the best services in the East is attested to by its effective information warfare; not just in regards to making espionage cases public, but also the severity of justice: spies usually get the maximum penalty."
"Estonian counterintelligence is said to be one of the most effective in NATO, begging the question as to the reasons for his effectiveness. Starting from square one, using extreme vetting as well as the de-Sovietization of the security apparatus certainly helped. [
Pretēji Latvijai, kur drošības dienestus veidoja bijušie VDK darbinieki, piemēram, VDK pretizlūkošanas daļas virsnieks Andris Trautmanis]"
"It is known that Russian diplomats catalogue and detail all the bridges in southern Estonia lying on the east-west line. Their focus is upon structures along the expressway connecting the Russian border with the Baltic Sea and the strategic railway line."
"Diplomatic status is increasingly rare, while more and more often they are illegals operating in the country or agents operating under the cover of being businessmen and journalists. Due to Moscow’s wariness of Estonian counterintelligence, Russian case officers usually meet their informants in third countries."
https://warsawinstitute.org/estonian-spy-hunters/Tas tā, runājot par "katrai valstij savi risinājumi".