Finally, the main protagonist of the story describes how very small changes to the letter caused it to be hidden from the police's eyes, even when they saw it, simply since it didn't look like what they thought it should.
They saw it. This is what the main protagonist of the story describes. It didn't look like what they thought. It should. This is what the main protagonist of the story describes. Very small changes to the letter caused it to be hidden from the police's eyes.