“I threw it into the river. . . .”
That story was created by Richard Durham (who was an editor of a Nation of Islam newspaper) in his “autobiography” of Ali, which did not have Ali’s input–and which he did not even read himself until after it was published.
Ali, did, however, agree to go along with the story for all these years.
The truth was that it had truly been lost.
Recent biographies by David Remnick and Thomas Hauser (with whom the Champ collaborated) have more details.