(CNN) The discovery of an East German secret police ID card wouldn't normally attract much attention, but things get a lot more interesting when it's Vladimir Putin's.

Issued in 1985, the document belonged to the then mid-ranking Soviet officer, now the President of Russia. At the time, Putin worked for the KGB spy service as a liaison with the East German State Security Service (Staatssicherheitsdienst), nicknamed the "Stasi."

From 1985 to 1990, Putin was stationed in Dresden, East Germany. The German newspaper Bild says the ID card found in the archives proves Putin was working for the Stasi, but the Stasi Records Agency (BStU) says it served a purely practical purpose.

The back of the ID card in question.

Putin in a KGB uniform, around 1980.

Spokeswoman Dagmar Hovestädt told CNN via telephone that Putin would have used the ID card to access Stasi facilities. He served in East Germany as a liaison officer, said Hovestädt, facilitating consultation between friendly intelligence services.

"In the 15 districts of East Germany the KGB representatives thus received access to the Stasi district office buildings," reads an email statement from the BStU. "This was the case for Vladimir Putin as well."

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