what does Mr.Nathan Radley know about the intrubers in his garden?

Mr Radley knows nothing about the intruders in his garden. Had he known they were children, he wouldn't have shot at them.

Miss Stephanie and the neighbors believe a black man was trespassing at the Radley's, citing that no one else would be caught about in someone's yard at that time of night. Unfortunately, this only cements the prejudice we see within the community and foreshadows what the opinions and beliefs of the community will be at Tom's trial.