Looking for a 1970s ya fiction book about a girl who died in an apartment house fire. Everyone thought that she was a hero because she alerted the other tenants to the fire so they could get out. Actually, it was her brother who had done the alerting while she went back to her apartment to get her shoe box of paper doll families. This was a much darker sequel to a book about a brother, a sister and another girl. Think the title may have been something like “The truth about (girl’s name)”, but not positive. Don’t remember author but know I read it right after it came out somewhere between 1969 and 1980.