The Adventure of the Golden Pince-Nez

A murder was committed at the old professor Coram’s house. His secretary Smith was killed while the professor was still in bed. Coram would have been the first suspect if it was not for the fact that he was an invalid who could not move. Inspector Hopkins got to a dead end in the investigation so he reached out for help from Watson and Holmes. The only evidence they found was a pince-nez. Can this be enough for them to solve the case?
"The Adventure of the Golden Pince-Nez" is a part of "The Return of Sherlock Holmes".
Sir Arthur Conan Doyle (1859-1930) was born in Scotland and studied medicine at the University of Edinburgh. After his studies, he worked as a ship’s surgeon on various boats. During the Second Boer War, he was an army doctor in South Africa. When he came back to the United Kingdom, he opened his own practice and started writing crime books. He is best known for his thrilling stories about the adventures of Sherlock Holmes. He published four novels and more than 50 short-stories starring the detective and Dr Watson, and they play an important role in the history of crime fiction. Other than the Sherlock Holmes series, Doyle wrote around thirty more books, in genres such as science-fiction, fantasy, historical novels, but also poetry, plays, and non-fiction.