We have a theory, but we haven't found a smoking gun yet.

When Prophet's place in Decatur, Georgia was raided in July 1989, there was the E911 Document, a smoking gun. And there was Prophet in the hands of the Secret Service, doing his best to "explain."

I now turn to the role and results of our current inspections. Evidently if we had found any ‘smoking gun’ we would have reported it to the Council.

It's all over the blogosphere and Air America, the left-wing talk radio network: This is the smoking gun of the Iraq war. It is proof positive that President Bush was determined to invade Iraq the year before he did so

A Nobel prize-winning US biologist, who has been widely quoted describing a “smoking gun” to support the thesis that Covid-19 was genetically modified and escaped from a Wuhan lab, has said he overstated the case.

Smoking gun

Meaning

Noun

Origin