The Circular Study

The reclusive owner of a distinguished house is discovered stabbed to death in the circular study at the heart of that house. The only other occupants are a deaf-and-dumb butler and a caged starling that can parrot occasional words it hears. Aided by some of Amelia's insights but more especially by an ambitious young cop, who displays exemplary enterprise and deductive skills, Gryce doesn't take too long to discover who the murderer is. (Goodreads)