According to Harper Lee, when the children went to the Radley place, who did they hear laughing? I think that it was Miss Crawford...not Boo. Look at the page #'s and chapter for reference.

We can infer from the following quote that the laughter was in fact Boo's.

"The first reason happened the day I rolled into the Radley front yard. Through all the head-shaking, quelling of nausea and Jem-yelling, I had heard another sound, so low I could not have heard it from the sidewalk. Someone inside the house was laughing." (Chapter 3/ Page 22)