When Facebook is suspicious about an account, it asks the owner to prove his identity, even if he has the correct password.

WSJ: Spam Finds a New Target

But after years as a slave and without any document to prove his identity to Georgian police, he stopped trying to escape.

BBC: Slave of the Caucasus

Prosecutors, however, say they have documents which prove his Nazi background, including an SS identity card which shows he was posted to the death camp in Sobibor in 1943 and many witness testimonies.

BBC: Demjanjuk facing Germany charges