Tuesday, September 6, 2022

96 - Fingerprinting

【指紋採取、shimon saishu】
[Lit. "Fingerprint harvesting"]

Fingerprints are said to be unique, even for identical twins, hence why they are used in criminal investigations.

The fingerprints of those who have once committed a crime are collected and stored as data, and any fingerprints left at a crime scene are then compared with the data on the record so that if the criminal was arrested before, they can be identified again.


Japan began using fingerprints to solve crimes in 1979.

A doctor working in Tokyo named Henry Faulds was the first to identify a criminal using fingerprints left behind at the scene of a robbery.


Various chemicals are used to detect fingerprints at crime scenes. The most famous, typically employed in dramas, are vegetable black and aluminum powder, both used to collect fingerprints left on smooth, level surfaces.

Vegetable black is a carbon powder mainly used for lightly pigmented objects, while aluminum, formed of fine silver particles, is utilized on darkly colored objects.


In turn, those who break the law will have the ten fingers on both hands fingerprinted by the police after being arrested.

This fingerprinting procedure applies to all criminal offenses, from minor offenses such as shoplifting and bicycle theft to speeding.


In addition, in order to narrow down the identity of the culprit, fingerprints are also collected from people considered necessary for the investigation, such as family members of the victim and the related parties at the scene of the crime. However, it is possible to refuse this procedure as it is optional.

Fingerprints collected this way will be temporarily stored in the police database, but will be deleted as soon as the fingerprint's owner is found to be unconnected to the case.

They are also deleted in cases where the statute of limitations has expired and when the convicted person is over 75 years of age.


Fingerprinting will continue to be extremely helpful to criminal investigations since, in recent years, it has become possible to detect fingerprints attached to cloth and left in the human body.

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