Search/Recent Changes
DBTropes
...it's like TV Tropes, but LINKED DATA!

Locard's Theory

 Locard's Theory
type
FeatureClass
 Locard's Theory
label
Locard's Theory
 Locard's Theory
page
LocardsTheory
 Locard's Theory
comment
Every contact leaves a trace. Every time one object comes in contact with another object, it takes something from that object or leaves something behind.
Principle which underwrites modern forensic science. The reason that criminalists look for fingerprints, DNA, soil samples, fibers, and all the evidence that falls into the category of "trace".
In real forensics, this is a very general principle from which we learn nothing more than that it makes sense to look for trace evidence.
In TV, it is always literally true. Every crime scene has an abundance of fibers, soil, DNA, bodily fluids, and fingerprintable air.
This representation of the Locard principle is one of the reasons for The CSI Effect.
In works that portray Functional Magic, Locard's Theory is a subset of the magical principle known as the Law of Contagion.
 Locard's Theory
fetched
2024-03-14T18:31:48Z
 Locard's Theory
parsed
2024-03-14T18:31:48Z
 Locard's Theory
processingComment
Dropped link to fridgelogic: Not an Item - FEATURE
 Locard's Theory
isPartOf
DBTropes
 Locard's Theory / int_13d84dd9
type
Locard's Theory
 Locard's Theory / int_13d84dd9
comment
Naoki Urasawa uses this trope in another of his suspense manga, the Astro Boy-inspired Pluto. The fact that no trace evidence can be found at any of the murder scenes leads the investigators to conclude that the Serial Killer they're looking for is a robot.
 Locard's Theory / int_13d84dd9
featureApplicability
1.0
 Locard's Theory / int_13d84dd9
featureConfidence
1.0
 Astro Boy (Manga)
hasFeature
Locard's Theory / int_13d84dd9
 Locard's Theory / int_2221ecbd
type
Locard's Theory
 Locard's Theory / int_2221ecbd
comment
As well as Mac Taylor.
 Locard's Theory / int_2221ecbd
featureApplicability
1.0
 Locard's Theory / int_2221ecbd
featureConfidence
1.0
 CSI: NY
hasFeature
Locard's Theory / int_2221ecbd
 Locard's Theory / int_26dbf2a9
type
Locard's Theory
 Locard's Theory / int_26dbf2a9
comment
Mentioned numerous times in Jeffrey Deaver's Lincoln Rhyme novels.
 Locard's Theory / int_26dbf2a9
featureApplicability
1.0
 Locard's Theory / int_26dbf2a9
featureConfidence
1.0
 Lincoln Rhyme
hasFeature
Locard's Theory / int_26dbf2a9
 Locard's Theory / int_29516906
type
Locard's Theory
 Locard's Theory / int_29516906
comment
Possibly the earliest TV instance of this is an episode of Dragnet where Sgt. Joe Friday was accused of shooting a suspect unprovoked. His dogged insistence on "he must have left something behind" caused investigators to eventually discover the bullet the suspect had fired. They realized that a line under a shelf was not a carpenter's pencil mark, but a trace from the bullet. It had pushed the shelf up just enough to hide the bullet hole
The question of why the suspect's gun would appear unfired is left as an exercise to the viewer. Regardless of whether it was a revolver or automatic an unfired round would still be present, in the form of a spent shell casing lying somewhere or inside the revolver. In any case, drawing a weapon against a police officer is a death sentence most of the time, whether the cop fired first is irrelevant.
 Locard's Theory / int_29516906
featureApplicability
1.0
 Locard's Theory / int_29516906
featureConfidence
1.0
 Dragnet (Franchise)
hasFeature
Locard's Theory / int_29516906
 Locard's Theory / int_39bc9c8a
type
Locard's Theory
 Locard's Theory / int_39bc9c8a
comment
Cited verbatim by Sportello to Bigfoot in Inherent Vice.
 Locard's Theory / int_39bc9c8a
featureApplicability
1.0
 Locard's Theory / int_39bc9c8a
featureConfidence
1.0
 Inherent Vice
hasFeature
Locard's Theory / int_39bc9c8a
 Locard's Theory / int_468bebb0
type
Locard's Theory
 Locard's Theory / int_468bebb0
comment
Used in a form in the Discworld novel Feet of Clay. Golems don't have fingerprints, but they do have traces of where they usually hang out.
 Locard's Theory / int_468bebb0
featureApplicability
1.0
 Locard's Theory / int_468bebb0
featureConfidence
1.0
 Discworld
hasFeature
Locard's Theory / int_468bebb0
 Locard's Theory / int_5c66fff9
type
Locard's Theory
 Locard's Theory / int_5c66fff9
comment
In Neverwinter Nights 2, your investigation into the Ember massacre partly involves a magical version of this.
 Locard's Theory / int_5c66fff9
featureApplicability
1.0
 Locard's Theory / int_5c66fff9
featureConfidence
1.0
 Neverwinter Nights 2 (Video Game)
hasFeature
Locard's Theory / int_5c66fff9
 Locard's Theory / int_731993f
type
Locard's Theory
 Locard's Theory / int_731993f
comment
CSI-verse:
CSI: Miami: Mentioned by name at least twice.
CSI:
And once by the villain.
And at least once by Grissom.
As well as Mac Taylor.
 Locard's Theory / int_731993f
featureApplicability
1.0
 Locard's Theory / int_731993f
featureConfidence
1.0
 CSI-verse (Franchise)
hasFeature
Locard's Theory / int_731993f
 Locard's Theory / int_892aa56a
type
Locard's Theory
 Locard's Theory / int_892aa56a
comment
Murdoch Mysteries: Early in the first season episode "Bad Medicine", Constable Crabtree speaks a bit despairingly of the culprit's escape from a murder scene without a trace. Murdoch reassures him thusly:
 Locard's Theory / int_892aa56a
featureApplicability
1.0
 Locard's Theory / int_892aa56a
featureConfidence
1.0
 Murdoch Mysteries
hasFeature
Locard's Theory / int_892aa56a
 Locard's Theory / int_8ba4613a
type
Locard's Theory
 Locard's Theory / int_8ba4613a
comment
Put to good use in Death Note; the reason it's so difficult to track down Kira is that the Death Note kills without leaving any physical traces, so L had to look for a culprit based on why the killings occurred the way they did. On the other hand, L was able to use forensic evidence against Misa because of the traces she left on the Second Kira tape, even though she had arranged for someone else to get their fingerprints on it.
 Locard's Theory / int_8ba4613a
featureApplicability
1.0
 Locard's Theory / int_8ba4613a
featureConfidence
1.0
 Death Note (Manga)
hasFeature
Locard's Theory / int_8ba4613a
 Locard's Theory / int_9d7264f
type
Locard's Theory
 Locard's Theory / int_9d7264f
comment
CSI: Miami: Mentioned by name at least twice.
 Locard's Theory / int_9d7264f
featureApplicability
1.0
 Locard's Theory / int_9d7264f
featureConfidence
1.0
 CSI: Miami
hasFeature
Locard's Theory / int_9d7264f
 Locard's Theory / int_aecab
type
Locard's Theory
 Locard's Theory / int_aecab
comment
Central to Gattaca.
 Locard's Theory / int_aecab
featureApplicability
1.0
 Locard's Theory / int_aecab
featureConfidence
1.0
 Gattaca
hasFeature
Locard's Theory / int_aecab
 Locard's Theory / int_c6dbe98e
type
Locard's Theory
 Locard's Theory / int_c6dbe98e
comment
That a man cannot stay somewhere without leaving some kind of trace is a mantra of Inspector Lunge in Monster. Of course, when it comes to Johan, it's not that simple. In fact, this is part of what gets him to trust the doctor's story about Johan. He says something earlier about how "nothing short of a demon" could go out of an area without leaving a trace. Johan apparently was in the area, but his room is so totally clean that he is in fact the "demon" of the story.
 Locard's Theory / int_c6dbe98e
featureApplicability
1.0
 Locard's Theory / int_c6dbe98e
featureConfidence
1.0
 Monster (Manga)
hasFeature
Locard's Theory / int_c6dbe98e
 Locard's Theory / int_cac1f772
type
Locard's Theory
 Locard's Theory / int_cac1f772
comment
CSI:
And once by the villain.
And at least once by Grissom.
 Locard's Theory / int_cac1f772
featureApplicability
1.0
 Locard's Theory / int_cac1f772
featureConfidence
1.0
 CSI
hasFeature
Locard's Theory / int_cac1f772
 Locard's Theory / int_da52a723
type
Locard's Theory
 Locard's Theory / int_da52a723
comment
In Rivers of London, all magical workings leave vestiga that another magic user can sense. In one of the comics, Peter describes checking for vestiga at a possibly-magic crime scene as the magical equivalent of Locard.
 Locard's Theory / int_da52a723
featureApplicability
1.0
 Locard's Theory / int_da52a723
featureConfidence
1.0
 Rivers of London
hasFeature
Locard's Theory / int_da52a723
 Locard's Theory / int_ef076a36
type
Locard's Theory
 Locard's Theory / int_ef076a36
comment
In one episode of Star Trek: Voyager there was NO TRACE at all on the crime scene. Not a single molecule out of place, handily detected by their Everything Sensor. The murderer was a hologram.
 Locard's Theory / int_ef076a36
featureApplicability
1.0
 Locard's Theory / int_ef076a36
featureConfidence
1.0
 Star Trek: Voyager
hasFeature
Locard's Theory / int_ef076a36

The following is a list of statements referring to the current page from other pages.

 Locard's Theory
processingCategory2
Laws and Formulas
 Gattaca / int_12476700
type
Locard's Theory
 Dragnet (Franchise) / int_12476700
type
Locard's Theory
 A Certain Magical Index / int_12476700
type
Locard's Theory
 Lincoln Rhyme / int_12476700
type
Locard's Theory
 RepairmanJack
seeAlso
Locard's Theory
 Death Note (Manga) / int_12476700
type
Locard's Theory
 Monster (Manga) / int_12476700
type
Locard's Theory
 Pluto (Manga) / int_12476700
type
Locard's Theory
 Crossing Jordan / int_12476700
type
Locard's Theory
 Murdoch Mysteries / int_12476700
type
Locard's Theory
 Picket Fences / int_12476700
type
Locard's Theory