Marina said Oswald showed her the notebook a few days after the attempt on Walker. He must have destroyed the notebook, but retained three photographs which Marina said she had seen in the notebook. Opinions vary on her credibility.
He did not destroy the notebook.... It was photographed among the evidence at the police station on the evening of 11/22/63.....apparently the photo of the 57 Chevy in Walker's parking area fell out of the notebook and someone simply laid it on top of the note book .
When Marina visited Lee in Jail on Saturday afternoon, Lee was concerned about that blue note book and told Marina to keep it safe because there were important documents in it. Lee didn't know that the police already had possession of the notebook.