Actually, two characters met their demise in Chapter 8 of Harper Lee's To Kill a Mockingbird. The mother of one of the novel's most important characters passed away.
Old Mrs. Radley died that winter, but her death caused hardly a ripple--the neighborhood seldom saw her, except when she watered her cannas.
It snowed during Chapter 8, a rarity in Maycomb, and during the extreme cold snap Miss Maudie's house caught fire. One of the novel's most comic characters succumbed due to the fire. Earlier in the day, Jem and Scout had constructed a snowman of dirt and snow. Because of its anatomical body parts (or lack thereof), it was nicknamed the "Morphodite Snowman." The heat left only Miss Maudie's sunhat--"suspended in a thin layer of ice, like a fly in amber"--and her hedge-clippers as a reminder of the "Morphodite."
You can find the answer to this question right at the beginning of the chapter. The answer is that it was "old Mrs. Radley" who died.
As far as the people of Maycomb are concerned, the death of Mrs. Radley is not really much of a big deal. The reason for this is that she had stopped being much of a part of the community. No one really even saw her except when she came out to water her flowers.
The Finch kids decide that Boo killed her, but Atticus disappoints them by saying it was natural.
In Chapter 8 of To Kill a Mockingbird, Scout narrates that old Mrs. Radley has died.
Since Mrs. Radley has been reclusive, as have all the others in her family, her death little affects the neighborhood. She has previously only appeared when she waters her cannas, flowering plants that thrive in the South. Of course, Jem and Scout have conjured the idea that Boo has had something to do with her departure, but Atticus disabuses them of this notion. After he returns from the Radley house, he informs his children that Mrs. Radley has died of natural causes.
Of course, the children are also curious about another member of the Radley family, but they argue over who will approach their father. Finally, Scout asks, "Atticus, did you see Mr. Arthur?" This question is met with a stern look over the newspaper as Atticus replies, "I did not." After this chilly response, the children ask no more questions.