The Girl is Murder by Kathryn Miller Haines 342 pages

Which girl is murder? It is 1942 and Iris is experiencing life upheaval. Her father lost his leg at Pearl Harbor. Her mother committed suicide in a hotel room. Her father takes her from her comfy life with her Aunt and Uncle to live with him in a room in a rooming house. She has to leave her private school and go to public school where there are BOYS! Money is very tight and she would like to help her father at his new career as a private  detective. Her first helpful efforts are rejected by him although she has great instincts for the business. When a classmate who robbed her locker on the first day of school goes missing, she decides to go "undercover" with the guy's ex-girlfriends. The language is fun -- very jivey and period specific -- one almost needs a glossary to keep up with the slang. Iris is plucky and sympathetic although her father seems to be a bit of a cold fish.Very entertaining historical fiction set in New York City, with an emphasis on mystery.