Former KGB officer Sergei Buchelovsky, his wife Natalya and their son Pavel, unsuccessfully applied for residence permits and turned to the court on Aug. 29.
Buchelovsky did not get the residence permit due to an Interior Ministry decree that former KGB officers and their families cannot receive permanent residence permits.
Buchelovsky's lawyer presented a secret document as evidence of his innocence on Oct. 26.
The document - an agreement signed in 1991 by the then Minister of State Raivo Vare and the KGB's special representative Vyatcheslav Shironin - had not been previously revealed and surprised even the current Minister of Internal Affairs Tarmo Loodus. Loodus said he had heard about the existence of the document but never saw it.
Loodus convened a commission of four specialists, including coordinator Erik-Niiles Kross, Chairman of the Parliament's constitution committee Mart Nutt, top lawyer Juri Raidla and Justice Minister Mart Rask.
The commission ruled that the document has no legal power in Estonia because it was signed before the current constitution was approved in July 1992.
The representative of the Russian ƒmbassy in Estonia said in an interview that, judging by the commission's decision, Estonia had not been subject to international law until July 1992 and all the agreements signed by the government before that time were not valid.
The embassy applied to the Estonian Ministry of Foreign Affairs on Nov. 7 to draw the ministry's attention to the international commitments of Estonia.
"Those arise from the agreement signed by the Estonian government and KGB on Dec. 18, 1991," read the official note.
The next day the Tallinn administrative court pronounced invalid the Interior Ministry's decree that did not allow the Buchelovsky family resident permits.
The court said the minister must reconsider Buchelovsky's case and make a new decision.
According to a court spokesperson, the ministry may appeal the ruling within 10 days and Buchelovsky's residence permit is not yet assured.
The decision of the Tallinn Administrative Court may become a precedent for all ex-employees of KGB.
Anu Adra, spokeswoman for the Interior Ministry, said the ministry considers several residence permit applications presented by ex-servicemen of the KGB.
"We are going to consider each case carefully and if there are any refusals we will ground them as fully as possible," she said.