Natalie Sumner Lincoln 
The Red Seal 

When a burglary suspect suddenly dies while in custody, Detective Ferguson is assigned to the case. Pretty widow Mrs. Brewster was seated in her big, high-ceilinged room at the Mc Intyre home. She was excitedly awaiting the interruption she was expecting, but the sound of a bell in the distance caused her to get up. The footman led Dr. Stone into the library, where Mrs. Brewster warmly greeted her cousin. As things go on in Natalie Sumner Lincoln's fascinating mystery, nothing is as it seems. There are several red herrings and red seals, which will keep you wondering until the very end of the book. Some of the other famous books from Natalie Sumner Lincoln are I Spy (1916), The Nameless Man (1917), The Moving Finger (1918), The Three Strings (1918), The Unseen Ear (1921) and many more.