Hard Evidence

The term "smoking gun" is a reference to an object or fact that serves as conclusive evidence of a crime or similar act, just short of being caught in flagrante delicto. "Smoking gun" refers to the strongest kind of circumstantial evidence, as opposed to direct evidence. Direct evidence would be eyewitness testimony of someone who saw an actus reus (the actual alleged act), while connected events (the preceding chase, etc.) are considered circumstantial.
The phrase originally came from the idea... more