What’s it “a sin to kill,” according to literary character Atticus Finch?

A Gregory Peck.
mockingbird
its a sin to kill a mockingbird
Have you read the book...have you looked at the title?
a mockingbird
That would be a mockingbird, which exists only to sing so beautifully :)
Oh my god, it's the effin' name of the book! Come on! Please read... Knowledge is power...
Mockingbird

or - a one armed black man


Answer:
Mockingbird is the correct answer for radio trivia. 100.3 KILT