Smoking Gun

The introduction of a key piece of evidence at the climax of a trial. Particularly, it is evidence that renders moot everything that has gone before or would have rendered the whole trial unnecessary from the beginning because it clearly implicates (or absolves) the defendant. It can come in two styles:


 * A person introduces evidence in the case or at least in a different light, and this inevitably shows the perpetrator for the criminal due to this evidence being so crucial. In this case however the evidence was already in the system and therefore in reality is totally legal. Most lawyers will not make fly by statements or ask different questions they have not researched however as in reality this can lead to losing a case because of an unexpected answer that can turn the tables.
 * A person introduces evidence randomly WITHOUT anyone knowing about it beforehand, even the judge. The evidence is absolutely crucial, and even by existing in the room at the exact moment, the perpetrator is either found guilty, or exposed. If the perpetrator is not the defendant or the prosecution, expect them to be in the courtroom when this evidence is shown, and the bailiff and security will get them before they can make any motion to escape. In real life introducing evidence in this manner is completely illegal to the system, and can cost the defense or prosecution the case, get the case mistrialed, set for a new date, or given a new jury. Not that that matters in fiction. Sometimes justified or hand waved by the prosecutor and/or the judge being informed of the existence of such a smoking gun, and if not cooperating, at least acquiescing to the Courtroom Antic needed to bring it in.

Sometimes other courtroom antics are pulled to buy time if it is known the Smoking Gun will arrive soon.

Comic Books

 * Done literally in New Warriors. Vance, a telekinetic, is on trial for the murder of his abusive father. The defense claims it was an accident, Vance was striking out in self-defense with his badly-tuned powers. The prosecuter pulls a pistol and fires at Vance's face. Vance mentally freezes the gag pistol and, unfortunately, the very smoke emanating from it. Stopping the smoke gets him sent away. The prosecuter remains unpunished.
 * In Youngblood Judgment Day, Toby King introduces the book of Hermes, a book containing all of history that can be used to alter the future -- or the past. He'd spent the entire trial trying to prove that the theft of the book was the true motive for Riptide's murder, and finally had proof of both this and his client Knightsabre's innocence: a passage written by to implicate Knightsabre in the crime, as proven by the fact that it describes him writing it.

Film

 * The film My Cousin Vinny ends with a classic Smoking Gun revelation, in which Vinny discovers a piece of evidence that proves that his clients couldn't have committed the murder, which leads to the further revelation that the actual perpetrators have already been arrested for an unrelated crime. At that point, it doesn't even have to go to the jury -- the prosecuting attorney dismisses the charges against Vinny's clients.
 * The evidence had already been introduced, it's just that no one had noticed the key piece of information hidden within it, until then.
 * Used literally in Bee Movie. Barry's friend even has to buy time, and the defending lawyer demands evidence (despite there already being evidence) of a smoking gun. Barry shows up with a smoke gun used to calm down honeybees. Bees win the case against humans.
 * Miracle on 34th Street: A pair of post office employees hear about a man on trial claiming to be Santa Claus, and decide to ease their workload by sending him the numerous "dead letters" written to Santa. His lawyer then claims that this constitutes his client being recognized as Santa Claus by an official government body.
 * Depending on your views on animal rights, you could classify this as a surprise witness, but in the Three Stooges' short Disorder in the Court, a parrot is discovered in the course of the trial with a letter tied to its leg, revealing the true killer and freeing their client.
 * In the film Legally Blonde towards the climax, Elle manages to pull one hell of a witness testimony and succeed just as she wanted.

Literature

 * The Lord Peter Wimsey mystery novel Clouds of Witness ends with a Smoking Gun, namely
 * In John Hemry's Rule of Evidence, Paul Sinclair dredges up evidence at the last moment that the newly installed system on the ship could have caused the problem they were blaming on sabotage. Specifically, the evidence includes a warning of problems the system could cause ... and the description in the warning is essentially identical to what actually happened. Someone in the government had concealed that evidence; the prosecutor and the judge were NOT happy with whoever it was.
 * Mark Twain's Pudd'nhead Wilson features the last-minute introduction of forensic evidence that not only solves the case on trial, but exposes another, unrelated deception that had gone undetected for twenty years.
 * In the trial of Tycho Celchu in the X Wing Series novels, there are two smoking guns. The first is a surprise witness (Who the prosecution and defense were both fully aware of and trying to bring in, it's just that he had only come forward as a witness less than a day before), who was killed before he could testify. The other is yet another surprise witness, who neither prosecutor or defense knew about until he walked into the courtroom -.

Live Action TV
"Meg Craddy: (Indicating the pregnant villager) This is an example of Henry Blake's work! Blake: (aside to himself) Great, That's all I need now!"
 * In the M*A*S*H episode "Snappier Judgment", Klinger is court martialed for theft and is about to be convicted. However, at the last second, Hawkeye, BJ and Military Police officers, dragging in the true culprit, charge in with a photograph that proves that their prisoner, and not Klinger, is the thief.
 * In an earlier episode, Majors Burns and Houlihan managed to have Colonel Blake arrested for "giving aid and comfort to the enemy". Hawkeye and Trapper arrived at the last minute with one of the "enemy" Blake was accused of aiding; a pregnant South Korean villager (North Korea was the enemy during that war, not South) who was dislocated when her village was bombed. When Burns refused to back down from his trumped-up charge, Hawkeye produced another smoking gun--a letter revealing Burns' affair with Houlihan, which he threatened to send to Burns' wife. The charges were dropped forthwith.


 * My Name Is Earl at Joy's trial the prosecutor introduces a surprise audio recording that shows Joy's bad character. You'd think there would be a law that says stuff like that has to be disclosed to the defence...
 * A variation in The Chicago Code, though not specifically confined to a trial. The CPD has been trying to indict Alderman Gibbons for months, and finally get the evidence to arrest him through a series of events that nearly gets their undercover cop killed. Then, when it turns out that the evidence isn't enough to convict him, they discover that Wysocki's brother collected rock-solid evidence of his corruption before he died, which makes everything else moot.
 * Get Smart had an episode where Maxwell Smart was a key witness in the trial of a KAOS agent. To discredit Smart, KAOS tricked him into doing things that made people around him perceive him as delusional. During the trial, Max realized a slip up the KAOS agent did that could expose the plot.
 * Boston Legal: One episode featured a witness for the prosecution surprising everyone by stating he filmed the crime. Despite the defence having not been previously made aware of the evidence, Sally Heap, the defendant's attorney, didn't object to its inclusion, which lead to her being berated by one of her superiors at Crane, Poole and Schmidt. She explained that she felt it wasn't the prosecutor's fault. (Which shows she doesn't know the rules, or she'd know that, prosecutor's fault or not, she could - and therefore should - have objected). Despite the defendant having been acquitted, this case is implied to be a reason Alan Shore didn't try to keep her from being fired in a later episode.
 * The Canadian TV series Exhibit A: Case Studies In Forensic Science played with this trope in its accounts of Canadian crime investigations. At some point during each episode, host Graham Greene would present what he called "Exhibit A", the piece of evidence that typically broke the case for the police.

Theater

 * Chicago: The District Attorney *thinks* he has a smoking gun, in the form of Roxie's diary being read into evidence by Velma Kelly.

Video Games

 * Sometimes shows up in Phoenix Wright: Ace Attorney, like in the second case of the first game.
 * Subverted at the end of case 4 of game 2, where
 * This is doubly subverted in case 3 of game 3, where
 * Subverted in additional case of first game against . Presenting certain piece of evidence that wasn't introduced to the court will cost you the case and end up with instant game over. First You have to.

Web Comics

 * Karate Bears found the smoking gun they had it.

Western Animation

 * The animation cell in a The Simpsons episode which revealed the true creator of Itchy and Scratchy.
 * In one episode of Gargoyles: The Goliath Chronicles, Goliath clears his name of jewelry theft by conning a confession out of the real thief and getting it on tape, then arriving in the courtroom with the thief and the tape.
 * A repeated Christmas special by Cartoon Network Grandma Got Run Over by a Reindeer has the grandson Jake clearing Santa's name with surprise evidence and no backing from anyone other than his own knowledge by proving the real culprit  Almost as if the writers knew this was impossible, the prosecution attempts to object, and the judge never acknowledges that he said anything and let's Jake keep talking.

Real Life

 * The infamous Watergate scandal. U.S. President Richard Nixon was ultimately forced to give up a tape recording that proved irrefutably that he did indeed try to cover up his participation in the breaking in of the Watergate building. Rather than face impeachment trials, Nixon resigned.