History Main / MotiveEqualsConclusiveEvidence

* Also similarly, in ''Film/LegallyBlonde'', the widow's defense team pretty much assumes she's guilty or at least had motive since it looks like she was a GoldDigger to a rich older husband. Except, as Elle points out, she was already well off as a successful fitness instructor with popular videos. Plus she seemed to genuinely care about her husband and claims he was great in bed. [[spoiler:The real killer was his daughter who was planning on shooting her stepmother (resenting her for being the same age as her) but accidentally shot her father.]]

* In the 1976 ''Helter Skelter'', District Attorney Vincent Bugliosi puts a strong emphasis on the motive for Charles Manson and his followers for the Tate and [=LaBianca=] killings but that is because the motive itself is so bizarre (Manson wants to start an apocalyptic race war) so it's important to establish that Manson had that motive and is willing to go to such lengths to achieve it.

** Northern Water Tribe members are suspected for bombing the Southern Water Tribe cultural center during a peaceful protest made by Southerners. Mako knows better, witnessing that the perpetrator was a firebender and identifying who he is as well as his affiliation with a bending triad. Other cops on the police force tell Mako to quit because it was clear that the Northerners did it. This poor judgement is portrayed as [[CorruptCop laziness on their part]].

* In the ''Series/StarTrekDeepSpaceNine'' episode "Rules of Engagement" Worf undergoes a hearing on whether he'll be extradited to the Klingon Empire for blowing up one of their transports after it decloaked in front of the ''Defiant'' during a firefight. Under Federation law, this is an open-and-shut case, and Worf is clearly innocent of murder. Under ''Klingon'' law, the motive of the killer is what is important (as in, did you kill out of duty or bloodlust?), and their lawyer somehow convinces the Starfleet admiral in charge of the proceeding to let him go ahead with that line of questioning. [[spoiler:Sisko later dresses him down for even firing on an unidentified target when he knew there might be civilian ships in the area]].

** The prosecutors often don't provide a motive for why the defendant would've committed the murder, instead just using the evidence and testimony gathered by the police investigation. Sometimes, when the real murderer is caught, you don't learn their motive until after they're arrested and you're waiting for the judge to give the Not Guilty verdict. At other times, you have to provide a motive (and evidence that supports said motive) for the person that the defense attorney is accusing of being the real criminal.

* In the ''LightNovel/LordElMelloiIICaseFiles'', this trope -- referred to as the question of "[[ArcWords whydunit]]" -- is invoked and [[JustifiedTrope justified]]. Magecraft can do almost anything (specifically, anything that could ''in theory'', according to current science, be done with unlimited time, effort, and resources by mundane means), meaning that when your suspect pool consists mainly of magi, almost literally anyone would have means or opportunity, and evidence can be extremely thin on the ground -- the culprit could've been someone across the world, a thousand years past, or even ''fictional'' (the latter two examples even get screen time in ''VideoGame/FateGrandOrder''). That said, Waver doesn't consider motive ''entirely'' conclusive; it's just by far the most important factor. This is in contrast to [[SecretPolice Hishiri Adashino]], who uses the trope as an end-all-be-all reasoning why someone might be the culprit, regardless if they even committed the crime.

* In the ''LightNovel/LordElMelloiIICaseFiles'', this trope -- referred to as the question of "[[ArcWords whydunit]]" -- is invoked and [[JustifiedTrope justified]]. Magecraft can do almost anything (specifically, anything that could ''in theory'', according to current science, be done with unlimited time, effort, and resources by mundane means), meaning that when your suspect pool consists mainly of magi, almost literally anyone would have means or opportunity, and evidence can be extremely thin on the ground -- the culprit could've been someone across the world, a thousand years past, or even ''fictional'' (the latter two examples even get screen time in ''VideoGame/FateGrandOrder''). That said, Waver doesn't consider motive ''entirely'' conclusive; it's just by far the most important factor.

* In the ''Series/StarTrekDeepSpaceNine'' episode "Rules of Engagement" Worf undergoes a hearing on whether he'll be extradited to the Klingon Empire for blowing up one of their transports after it decloaked in front of the ''Defiant'' during a firefight. Under Federation law, this is an open-and-shut case, and Worf is clearly innocent of murder. Under ''Klingon'' law, the motive of the killer is what is important (as in, did you kill out of duty or bloodlust?), and their lawyer somehow convinces the Starfleet admiral in charge of the proceeding to let him go ahead with that line of questioning.
** May be a subversion though. Worf [[spoiler: gets off because the Klingons had actually set the whole thing up with an empty transport and used a fake manifest of passengers killed in an earlier accident. Afterwards, Worf admits that he's not actually sure if he did it from duty or bloodlust, and Sisko dresses him down for even firing on an unidentified target when he knew there might be civilian ships in the area]].

* ''Series/{{Motive}}'' inverts this trope since the detectives usually don't discover the motive for the crime till the end of the episode and by that time they have a fair bit of evidence to convict the perpetrator. The show's gimmick is that we know from the start who the killer is but the reasons for the crime are hidden until the very end.
* This has been applied so many times on the ''Series/CSICrimeSceneInvestigation'' and the ''Franchise/LawAndOrder'' franchises (usually as a RedHerringTwist) that it would be easier to number the times it ''wasn't'' used. [[BeAsUnhelpfulAsPossible The suspects flying into a rage or shutting up]] ([[OnlyBadGuysCallTheirLawyers usually because a lawyer tells them to]]) when the motive is brought up (and in typical fashion of these shows, the interrogator is being rather cynical and [[DeadpanSnarker smart-mouthed]] about it) [[NotHelpingYourCase doesn't helps them in any way]]. [[DownerEnding And sometimes, even if innocent, by the time the investigators have conclusive evidence the damage has been done]].
** A lack of an alibi doesn't help either. Motive or not, most TV cops seem to think a suspect claiming he/she was "home alone or home alone with my wife/husband/sister/brother, etc" is tantamount to a confession since there really isn't a way someone can prove that and said spouse/sibling could be lying. As well as admitting that they were anywhere near the victim shortly before their death. Nevermind that a guilty person would be far more likely to ''lie'' about something like this. One especially bad example has Benson and Stabler showing up at the home of a man who had dinner with their murder victim and proceeding to accuse him of being both her lover and her killer -- with absolutely ''zero'' evidence to support either accusation.

* This has been applied so many times on the ''Series/CSICrimeSceneInvestigation'' and the ''Franchise/LawAndOrder'' franchises (as mentioned above, usually as a RedHerringTwist) that it would be easier to number the times it ''wasn't'' used. [[BeAsUnhelpfulAsPossible The suspects flying into a rage or shutting up]] ([[OnlyBadGuysCallTheirLawyers usually because a lawyer tells them to]]) when the motive is brought up (and in typical fashion of these shows, the interrogator is being rather cynical and [[DeadpanSnarker smart-mouthed]] about it) [[NotHelpingYourCase doesn't helps them in any way]]. [[DownerEnding And sometimes, even if innocent, by the time the investigators have conclusive evidence the damage has been done]].

* In ''Film/TheShawshankRedemption'', Andy Dufresne landed himself in jail for being suspected of the murder of his wife simply because he told her that [[SeeYouInHell he would see her in hell]] before [[DivorceInReno he would see her in Reno]]. [[MiscarriageOfJustice He also got sentenced]] [[IncriminatingIndifference because his shock at the events going on (and thus lack of expression) had the judge and jury believe he was a "stone-cold killer"]].
** There was also a preponderance of circumstantial evidence: she and her lover were murdered the same night as their argument, there was evidence placing him at the scene (and he was there, and had actually considered at least scaring them with a gun, before throwing it away in disgust with himself), he owned a gun which he couldn't produce for comparison and was never found... None of this is conclusive, but taken together, [[TruthInTelevision it's not implausible that a jury would convict him.]]

** In the sixth entry to the series, ''VisualNovel/PhoenixWrightAceAttorneySpiritOfJustice'', the killer of the fourth case says "I had no motive for killing the victim!" Defense attorney Apollo Justice mentally notes that it's a desperate last gasp since all of the evidence is pointing in their direction; the killer is just desperately trying to stall.

* Averted in ''Literature/WithoutRemorse''. Ryan and Emmett eventually realize that Kelly, who is a retired SEAL who has the skills to kill all the drug dealers in Baltimore, also has an excellent motive to murder all the drug dealers in Baltimore, and from that conclude that he is 'the Invisible Man', who has been killing all the drug dealers in Baltimore. But in the next paragraph, they openly admit that they have no real evidence, just a very convincing motive, so they have to keep investigating until they find some.

* In the ''LightNovel/LordElMelloiIICaseFiles'', this trope -- referred to as the question of "[[ArcWords whydunit]]" -- is invoked and [[JustifiedTrope justified]]. Magecraft can do almost anything (specifically, anything that could ''in theory'', according to current science, be done with unlimited time, effort, and resources by mundane means), meaning that almost literally anyone would have means or opportunity, and evidence can be extremely thin on the ground -- the culprit could've been someone across the world, a thousand years past, or even ''fictional'' (the latter two examples even get screen time in ''VideoGame/FateGrandOrder''). That said, Waver doesn't consider motive ''entirely'' conclusive; it's just by far the most important factor.

* Also similarly, in ''Film/LegallyBlonde'', the widow's defense team pretty much assumes she's guilty or at least had motive since it looks like she was a GoldDigger to a rich older husband. Except, as Elle points out, she was already well off as a successful fitness instructor with popular videos. Plus she seemed to genuinely care about her husband. [[spoiler:The real killer was his daughter who was planning on shooting her stepmother (resenting her for being the same age as her) but accidentally shot her father.]]

->''”Who benefits?”''
-->--'''Motto of {{Conspiracy Theorist}}s everywhere'''

[[folder:Anime/Manga]]
* In the ''LightNovel/LordElMelloiIICaseFiles'', this trope -- referred to as the question of "[[ArcWords whydunit]]" -- is invoked and [[JustifiedTrope justified]]. Magecraft can do almost anything (specifically, anything that could ''in theory'', according to current science, be done with unlimited time, effort, and resources by mundane means), meaning that almost literally anyone would have means or opportunity, and evidence can be extremely thin on the ground -- the culprit could've been someone across the world, a thousand years past, or even ''fictional'' (the latter two examples even get screen time in ''VideoGame/FateGrandOrder''). That said, Waver doesn't consider motive ''entirely'' conclusive; it's just by far the most important factor.
[[/folder]]

* In the ''LightNovel/LordElMelloiCaseFiles'', this trope -- referred to as the question of "[[ArcWords whydunit]]" -- is invoked and [[JustifiedTrope justified]]. Magecraft can do almost anything (specifically, anything that could ''in theory'' be done with unlimited time, effort, and resources by mundane means), meaning that almost literally anyone would have means or opportunity, and evidence can be extremely thin on the ground -- the culprit could've been someone across the world, a thousand years past, or even ''fictional'' (the latter two examples even get screen time in ''VideoGame/FateGrandOrder''). That said, Waver doesn't consider motive ''entirely'' conclusive; it's just by far the most important factor.

* In the [[LordElMelloiCaseFiles]], this trope -- referred to as the question of "[[ArcWords whydunit]]" -- is invoked and [[JustifiedTrope justified]]. Magecraft can do almost anything (specifically, anything that could ''in theory'' be done with unlimited time, effort, and resources by mundane means), meaning that almost literally anyone would have means or opportunity, and evidence can be extremely thin on the ground -- the culprit could've been someone across the world, a thousand years past, or even ''fictional'' (the latter two examples even get screen time in ''VideoGame/FateGrandOrder''). That said, Waver doesn't consider motive ''entirely'' conclusive; it's just by far the most important factor.

* In [[CaseFiles]], this trope -- referred to as the question of "[[ArcWords whydunit]]" -- is invoked and [[JustifiedTrope justified]]. Magecraft can do almost anything (specifically, anything that could ''in theory'' be done with unlimited time, effort, and resources by mundane means), meaning that almost literally anyone would have means or opportunity, and evidence can be extremely thin on the ground -- the culprit could've been someone across the world, [[FateGrandOrder a thousand years past, or even ''fictional'']]. That said, Waver doesn't consider motive ''entirely'' conclusive; it's just by far the most important factor.
[//folder]

Sometimes the suspect's motive is enough to incriminate him, even if no concrete evidence is presented or it doesn't add up. Quite possibly, an AmateurSleuth might have gone on a wild guessing spree and thought it made sense, but had only jumped to conclusions and ended up making baseless accusations. The sleuth's conclusions may have not necessarily been led by InsaneTrollLogic, but he forgot the big detail: you need actual solid evidence and other proof before going out and pointing fingers. In fiction, this is not always the case, and one can bypass all methods of proving who the perpetrator was if a given suspect's motive is reason enough.

Compare NotProven, where a lack of evidence allows a guilty party to go free; ConvictionByContradiction, when a flaw in the alibi implicates the suspect, and ConvictionByCounterfactualClue, when the evidence proving guilt is totally wrong in the first place. See also OccamsRazor, which states the simpler the solution the less likely it is to be wrong.

* Defied in ''WesternAnimation/{{Hoodwinked}}''. Red Puckett tells her side of the story. In her story, she thinks the Wolf is up to something bad involving a rash of recipe thefts because he's following her around, asking her personal questions, and she finds that creepy. Then Flippers tells Red they don't arrest people for being creepy. At the same time, the Wolf is a investigative freelance journalist who believes that ''Red'' and her Granny were behind the thefts on a misinformed tip from one of his informants. Both of them are innocent regarding the thefts and are subsequently released after their alibis are confirmed so that Flippers can identify the real culprit.

* ''Film/TheFugitive'': The fact that Richard Kimble would have gained something from killing his wife (namely, money--even though he was already pretty well off financially as one of the top ranked surgeons in Chicago) is [[MistakenForMurderer one]] [[HollywoodLaw of]] [[FrameUp the]] many reasons why the Chicago Police Department arrest him [[PoliceAreUseless and don't give a second thought]] [[BadCopIncompetentCop to continue the investigation]]. [[WhatTheHellHero Needless to say]], [[InspectorJavert Samuel]] [[SympatheticInspectorAntagonist Gerard]] is...pretty quick to make note of how stupid this is the first chance he gets to talk to the original investigating detectives. [[spoiler:[[MinorCrimeRevealsMajorPlot And turns out, she]] ''[[MinorCrimeRevealsMajorPlot did]]'' [[MinorCrimeRevealsMajorPlot die for money]]--just not ''hers''. And there's [[FridgeBrilliance the]] [[FridgeHorror fact]] [[UnfortunateImplications that]] [[DirtyCop the]] "one-armed man" was an ex-Chicago cop, raising the possibility the Chicago Police covered for one of their own...]]

* In the live action movie of ''Film/PhoenixWrightAceAttorney'', this shows up in the final trial, when Phoenix accuses [[spoiler:Manfred von Karma]] of murdering Gregory Edgeworth. The killer insists that without a motive, Wright has no grounds to accuse him of doing it. Played with in that Phoenix ''has'' provided good evidence that his suspicions are correct, and the insistence of a motive was the killer clutching at straws, since he figured no one could prove the reason he did it.

** The same trope shows up at the very climax of the book. In the first book, the mystery of Jon Arryn's death was the DrivingQuestion. At the end of that book, Ned Stark finds out that Cersei Lannister had powerful motives for wanting him dead and the ensuing fiasco leads to a CivilWar. Turns out, [[spoiler:that Cersei was framed at that time by Littlefinger, who later killed Joffrey and framed Tyrion for it. Being a MagnificentBastard, he used this to ensure that PoorCommunicationKills]].
* Averted in ''Literature/WithoutRemorse''. Ryan and Emmett eventually realize that Kelly, who is a retired SEAL who has the skills to kill all the drug dealers in Baltimore, also has an excellent motive to murder all the drug dealers in Baltimore, and from that conclude that he is 'the Invisible Man', who has been killing all the drug dealers in Baltimore. But in the next paragraph they openly admit that they have no real evidence, just a very convincing motive, so they have to keep investigating until they find some.

* The fifth Literature/FearStreet book actually inverts this. The protagonist's goal is to prove her half-brother innocent of murder, and refuses to go to the police without actual proof that [[spoiler: the victim's husband was the killer.]] However, it never seems to occur to her that the evidence she did uncover ([[spoiler: an affair, and plans to flee the country]]) would have at minimum hurt his credibility as a witness, and thus helped her brother's case. Something of a JustifiedTrope as she's a teenager, not a lawyer.

* ''Series/{{Psych}}'' more or less runs on this trope. The main character is usually hired by the police because of his ability to piece together things when there's little physical evidence. Most characters assume/are lead to believe its [[PhonyPsychic psychic powers]]. He'll get his suspect, rattle off his list of mostly, if not entirely, circumstantial evidence and usually get a confession out out of the perp. {{Lampshaded}} at least once when the police protest they'll actually need more than Shawn's "psychic" hunches to move forward in a case.

** A lack of an alibi doesn't help either. Motive or not, most TV cops seem to think a suspect claiming he/she was "home alone or home alone with my wife/husband/sister/brother, etc" is tantamount to a confession, since there really isn't a way someone can prove that and said spouse/sibling could be lying. As well as admitting that they were anywhere near the victim shortly before their death. Nevermind that a guilty person would be far more likely to ''lie'' about something like this. One especially bad example has Benson and Stabler showing up at the home of a man who had dinner with their murder victim and proceeding to accuse him of being both her lover and her killer--with absolutely ''zero'' evidence to support either accusation.
* In the ''Series/StarTrekDeepSpaceNine'' episode "Rules of Engagement" Worf undergoes a hearing on whether he'll be extradited to the Klingon Empire for blowing up one of their transports after it decloaked in front of the ''Defiant'' during a firefight. Under Federation law this is an open-and-shut case, and Worf is clearly innocent of murder. Under ''Klingon'' law, the motive of the killer is what is important (as in, did you kill out of duty or bloodlust?), and their lawyer somehow convinces the Starfleet admiral in charge of the proceeding to let him go ahead with that line of questioning.

** In the sixth entry to the series, ''VisualNovel/PhoenixWrightAceAttorneySpiritOfJustice'', the killer of the fourth case says "I had no motive for killing the victim!" Defense attorney Apollo Justice mentally notes that it's a desperate last gasp, since all of the evidence is pointing in their direction; the killer is just desperately trying to stall.

** Ahsoka Tano is accused this way in the final arc of the fifth season. Ahsoka starts out investigating a crime involving sabotage at the Jedi Temple and starts interrogating potential suspects. Ahsoka is accused of committing the crimes herself even though the evidence is dodgy: while interrogating a witness, the record shows her Force choking the witness when she was only scrambling to help the woman being Force-choked remotely; the audio was suspiciously cut off. Also, Ahsoka is reinforced as guilty when she is found in possession of the same bombs used in the sabotage, when she was actually going to search the warehouse for clues to their actual owner. She quickly grows disillusioned as she protests that she's being framed and her prosecutors are too ready to convict her just for being in the wrong place at the wrong time.