The Adventure of the Empty House

Ronald Adair, a quiet young man whose only hobby was playing cards, got killed. Watson attempted to crack the case but with no success. One day he decided to examine the area around the victim’s house and then he ran into a strange old man.
Who is he? Can it be the murderer who came back to the crime scene in disguise? Or the old man is simply a witness? Will Watson find out what happened by applying Holmes’ methods or this will not be enough?
You can find the answers in "The Adventure of the Empty House" which 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.