Isabel Egenton Ostrander (1883–1924) was a mystery writer of the early twentieth century who used, besides her own name, the pseudonyms Robert Orr Chipperfield, David Fox, and Douglas Grant. Christopher B. Booth is sometimes (falsely) credited as a pseudonym of hers.
She was born in New York City to Thomas E Ostrander and Harriet Elizabeth Bradbrook. Her Ostrander pedigree goes back to seventeenth century Kingston, New York.
Retired police detective McCarthy and his fireman best friend Denny Riordan solve the mysterious death of a valet. I like Isabel Ostrander, but this one did seem a bit gruesome towards the end. I liked the other McCarty books better than this one. My 2 cents.