The Adventure of the Six Napoleons

A series of break-ins occur in London. All of them have one thing in common - a bust of Napoleon is smashed. Inspector Lestrade comes to a dead end, so he reaches out to Holmes. The next break-in takes place. This time with a murder as well. In the victim's pocket they find a picture of an unknown man. Holmes and Watson's starting point is then the factory where the busts were produced. The two detectives manage to find out where the last three busts are.
Will they get in time to prevent the next crime? "The Adventure of the Six Napoleons" is a part of "The Return of Sherlock Holmes".