In Berlin, after WWII, money was short, supplies were tight, and it seemed like everyone was hungry. At that time, people were telling the tale of a young woman who saw a blind man picking his way through a crowd. The two started to talk. The man asked her for a favor: could she deliver the letter to the address on the envelope? Well, it was on her way home, so she agreed.
She started out to deliver the message, when she turned around to see if there was anything else the blind man needed. But she spotted him hurrying through the crowd without his smoked glasses or white cane. She was, naturally, suspicious, so she went to the police.
When the police paid a visit to the address on the envelope, they made a gruesome discovery. Three butchers had been harvesting human flesh and selling it to the starving people.
And what was in the envelope the man gave to the woman? A note, saying simply, "This is the last one I am sending you today."