The Wrong Letter

> The crime: The Home Secretary Sir James Watson was found shot in the head, inside his study which was locked from the inside. There was no apparent way in or out for the murderer to have been able to get into the room to commit the crime, nor a way to escape unnoticed. Further, the housekeeper Mrs. Simmons would certainly have heard any shot--but did not. What is going on here? How was the crime committed and by who?

>It will be the task of Superintendent Sinclair from Scotland Yard and his amateur sleuth friend Sylvester Collins, a barrister, to unravel the mystery.