Deduction Reasoning

Sherlock use the method by "Eliminating the Possibilities" to deduce and solve the mystery so he can draw the conclusion what happen in the crime.

Let's say for example. A man is found dead in his office. There is no sign of forced entry. The victim was stabbed. The investigators eliminate the possibility of a random robbery as nothing valuable seems to be missing. They also rule out a suicide as stabbing oneself in the back is highly unlikely. The only remaining possibility is that someone the victim knew had a motive to kill him and gained access to the office without causing a disturbance.