Looting Matters has been asking much the same thing. So King replies:
We don't know. King says that "nothing is known about the circumstances of its discovery," an admission that has raised red flags for other scholars.
... The papyrus now belongs to an anonymous collector who asked King to analyze it. King says three scholars have determined that the fragment is not a forgery, but that further tests will be conducted on the ink. The scholar also says that she will press the fragment's anonymous owner to come forward.One gets the feeling that King has been surprised by the media interest and the negative impact of the story. The present proprietor is probably wishing that there had not been such a high profile spread in the New York Times.