who says this quotes, then i saw the shadow...and does this quotes of boo radely come from a reliable or not ? why or why not

Scout is narrating the story. The information is correct because she is relaying information about an event she witnessed.

Then I saw the shadow. It was the shadow of a man with a hat on. At first I thought it was a tree, but there was no wind blowing, and tree-trunks never walked.