A landlord who unlocked an apartment after his letters announcing a rent increase went unanswered found the body of an elderly tenant, and police believe the man may have died three or four years ago, a newspaper reported.

The remains of the 93-year-old man, a former professor whose name was not released, were found Tuesday in a bed after the housing management company got the keys to his flat and made a visit after he failed to respond to letters requesting more rent, authorities were quoted as saying by the Kurier newspaper.

Investigators believe the man may have died as many as four years ago, police Lt. Col. Georg Rabensteiner was quoted as saying.

He said police found only old Austrian banknotes in the apartment, the report said. Austria, like many European Union nations, switched to the euro as its currency on Jan. 1, 2002.

Neighbors described the man as a recluse, the report said, citing police.

Rabensteiner said no one noticed earlier that he had died because automatic rent payments had gone out regularly from his bank account, which was constantly replenished with automatic deposits from his pension fund, the report said.

Neighbors in the apartment complex apparently did not find it unusual that junk mail was piling up outside his door, it added.