How is Ethel's apartment an important setting in the novel, While My Pretty One Sleeps?

One of the more visited scenes in the novel is Ethel Lambston's apartment. It is in this setting that Anthony della Salva murders Ethel then changes her clothes. Neeve visits this scene several times as she tries to deliver Ethel's new clothes. She later returns to help the investigators compile a list of the clothes missing from Ethel's closet. Douglas Brown, Ethel's nephew, takes up residence in Ethel's apartment beginning a couple of days after she is killed. It is in this apartment that he is confronted by Ruth who is trying to get the alimony check as well as the letter that she forced Seamus to write to Ethel back. Although the encounter happens before the novel starts, it is also in Ethel's apartment that Seamus has a fight with and punches his ex-wife.