Envelope

In Berlin, after World War II, 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 went to the police, who raided the address on the envelope, where they found heaps of human flesh for sale.
And what was in the envelope? “This is the last one I am sending you today.”