Who is the murderer in Blues for Mister Charlie?

James Baldwin's 1964 play, Blues for Mr. Charlie, found its basis in the 1955 murder of Emmett Till in Mississippi.
In the play's first act, middle-aged store owner Lyle Bittern, not incidentally Caucasian, is indicted for the murder of Richard Henry, a young African American and son of a pastor and civil rights leader. Parnell James, the editor of the local newspaper, assures Bittern that he will never be convicted. Their community is already charged with a racial tension that is only heightened by Bittern's arrest.
Through a series of flashbacks Baldwin sketches in the characters of both men, including Henry's ambivalence about the validity of violent self-defense and the apparent guilt of Bittern over the death of the husband of a woman who had been cheating with him.
The trial turns out to be a farce; witnesses lie without penalty, and there are no African-Americans on the jury, which renders a verdict of 'not guilty.' In a final flashback, Baldwin reveals that Lyle Bittern is, indeed, the murderer of Richard Henry.