Smoking gun

Metaphor for conclusive evidence of an act

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, while connected events are considered circumstantial.

This keyword could refer to multiple things. Here are some suggestions: