What does Mr. Nathan Radley know about the intruders in his garden? why does Miss Stephanie refer to a negroover whose head Mr. Nathan has fired

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 ome else would be caught about in someone's yard at that time of night. Unfortunate;y, this only cements the prejudice we as the reader see within the community and foreshadows what the opinions and beliefs of the community will be at Tom's trial.

I believe he did know about the intruders that's why he shot in the air.