a smoking gun

smoking gun

Indisputably incriminating evidence. Likened to a gun that is still smoking after having been fired. A smoking gun was revealed in the form of emails documenting the man's involvement in the money laundering scheme. So far the prosecutor has presented only circumstantial evidence, but she's expected to reveal a smoking gun against the defendant soon.
See also: gun, smoking
Farlex Dictionary of Idioms.

a smoking gun

COMMON If you talk about a smoking gun, you mean a piece of evidence which proves that a particular person is definitely responsible for a crime. The search for other kinds of evidence failed to produce a smoking gun. First of all, there's no smoking gun. In the course of our investigation we did not find a single piece of evidence.
See also: gun, smoking
Collins COBUILD Idioms Dictionary, 3rd ed.

a smoking gun (or pistol)

a piece of incontrovertible evidence.
This phrase draws on the assumption, a staple of detective fiction, that the person found with a recently fired gun must be the guilty party. The use of the phrase in the late 20th century was particularly associated with the Watergate scandal in the early 1970s involving the US President Richard Nixon . When one of the Watergate tapes revealed Nixon's wish to limit the FBI's role in the investigation, Barber B. Conable famously commented: ‘I guess we have found the smoking pistol, haven't we?’
1998 New Scientist This genetic smoking gun is evidence of a migration out of Asia that is hard to refute.
See also: gun, smoking
Farlex Partner Idioms Dictionary

a/the ˌsmoking ˈgun

something that seems to prove that somebody has done something wrong or illegal: This memo could be the smoking gun that investigators have been looking for.
See also: gun, smoking
Farlex Partner Idioms Dictionary
See also:
  • a/the smoking gun
  • smoking gun
  • the smoking gun
  • in the gun
  • pull a gun
  • pull a gun on (one)
  • gun-shy
  • hold a gun to (one's) head
  • hold a gun to head
  • hold/put a gun to somebody's head
References in periodicals archive
A Smoking Gun reporter discovered the breach and alerted the U.S.
Sealed records exposed on PACER
This leads to the ironic conclusion that--like not shredding paper documents--companies must retain their emails, even if they're keeping a smoking gun on their hands.
Business dilemma: email retention policy; new SEC regulations to address storing and restoring
The time to deal with a child--via tutoring, mentorship, internships, or simply talking and listening--is before isolation and alienation place a smoking gun in their blood-stained hands.
Stop the guns
I can't point to any one piece of evidence as a smoking gun and say 'here, this proves it.' Well I have an idea for a project that will give us a couple of smoking guns to bring to the national media." He explained, "I am proposing a quick and easy project that should produce...
Cowboys, camels, and kids: does advertising turn people into smokers?
When the Senate Governmental Affairs Committee called Secretary of the Interior Bruce Babbitt to testify in its campaign finance hearings this October, it looked as though Republicans might have at long last found a smoking gun in the Democratic fund-raising controversy.
If a smoking gun existed in this matter, Skibine held it.
Silent witness