BY Preeti Shah | September 07, 2022
Fingerprints have been in use for more than 100 years for personal identification. It is considered one of the most inexpensive identification techniques and acts like an identity card for each person.
Fingerprints are left at the crime scene or on the object that comes into contact with the criminal's fingers. They were legally accepted as a form of evidence in the court of law in the early 20th century.
It helps law enforcement agencies identify suspects and catch criminals.
There is no limit to the surfaces on which fingerprints can be found. You can often get influenced by misconceptions about fingerprint science leading to confusion.
So, here I will discuss a few less known fingerprint science myths and their complete explanation.
Hands play a major role in committing a crime. Hence the chance of finding fingerprints at the crime scene is much higher than any other type of evidence.
Even identical or fraternal twins with the same genetics have different fingerprint patterns. Hence, experts can easily identify them by analyzing their fingerprints.
Fingerprints are an important piece of evidence globally because of the following reasons:
The fingerprint patterns on the fingertips of each person are unique. No two fingers to date have been found to have a similar pattern.
The fingerprint pattern remains the same throughout the lifetime. The ridges appear before birth and remain constant till the death of a person.
As every person possesses a unique fingerprint pattern, this identification medium has gained a universal status.
Fingerprints cannot be imitated. The criminals make several efforts to forge fingerprints, but a forensic expert easily identifies them.
Fingerprints have ridges, and these ridges have different characteristics and patterns. It makes their classification possible.
Despite their global acceptance as an identification medium, various myths are associated with fingerprints.
Forensic investigators, law enforcement officials, judges, and the public have misconceptions about fingerprint development in the following areas, such as the effect of environmental factors like wind, rain, sunlight, temperature, humidity, etc., and the influence of time on fingermark's constituents.
All these factors sometimes take the investigation process in a negative direction.
It obstructs justice as investigators show less concern for developing fingerprints affected by such factors at the crime scene that set suspects and real culprits free.
Here I will discuss them in detail and see if they are right.
Myth: Only humans have fingerprints
Fact: Various animals except for humans, like koalas, gorillas, chimpanzees, etc., have unique fingerprints. A few animals like Koalas have fingerprints similar to human prints.
Myth: Fingerprints are everlasting
Fact: Though fingerprints are everlasting, there are a few skins and genetic conditions in which fingerprints get distorted or vanish. Sometimes if you work as a typist, do too many household chores, message a lot, etc., your fine ridge characteristics also diminish.
Myth: AFIS (Automated Fingerprint Identification System) do an accurate fingerprinting matching
Fact: AFIS compares the questioned fingerprint with the prints in its database. It provides the result that includes not one but several fingerprints identical to the print in question.
Now forensic expert compares ridge characteristics and patterns with the questioned print to deliver the perfect match. The process followed is known as ACE-V (analysis, comparison, evaluation, and verification). This method is highly accurate and reliable.
Myth: Experts compare all results given by AFIS with the questioned fingerprint
Fact: AFIS gives a list of similar matches in decreasing order of the number of similarity points. Experts only compare questioned print with the top results that show maximum similarity. It is because a sufficient number of features of friction ridge impressions from both questioned and reference print must match to conclude that source of origin is the same.
Myth: There are no limitations
Fact: Several conditions like bad weather affect the quality of latent prints. Too hot weather leads to excessive moisture, and cold weather leads to less moisture. In both cases, print mark quality is poor and unsuitable for recording. Print quality is also affected by rain and wind.
Sometimes due to excessive use of print-enhancing powders, ridges get smudged.
Also, you cannot evaluate the time the print was first formed, as prints can survive for a long time.
And you cannot rely on the AFIS system alone because you do not know if there will be any match to the print you are looking for in its database.
Myth: Soaked fingerprints get removed from the paper on wiping
Fact: People use several methods to wipe off fingerprints from paper. However, prints do not get removed. They only become invisible. They can only be destroyed if the paper is physically damaged. Chemical fingerprint development methods can make such prints visible.
Myth: It is impossible to remove fingerprints from paper
Fact: Soaked fingerprints cannot be removed. But prints on glossy paper can be removed if wiped out immediately after their formation. It is possible because prints do not get soaked instantly on a glossy or semi-absorbent surface.
Myth: No fingerprints are formed if you are wearing gloves
Fact: If you wear extremely thin disposable vinyl gloves, fingerprints can be left behind. Hence, even forensic scientists must wear thick rubber or white cotton gloves while investigating or handling questioned documents.
Myth: Ink blotting can make prints unidentifiable
Fact: Forensic experts use various light sources to reveal what is hidden behind the ink. Also, sometimes the ink gets absorbed into the print, making it more visible and permanent.
Myth: Latent fingerprints are always formed on touching the paper
Fact: Only touching paper cannot produce finger marks. Latent prints are invisible prints formed due to sweating. Without it, marks cannot be formed. Also, marks will not be formed if you sweat less or the paper is glossy.
Myth: Fingerprints get damaged on washing paper with water.
Fact: Merely immersing paper with prints in water does not destroy them. Paper fibers start to disintegrate in water upon swelling, and it takes several days under running water.
Putting paper in still water requires a few weeks to get completely destroyed. However, the thickness of paper and the material used also play a crucial role in the time it takes to disintegrate. Experts can develop prints if the paper is found in still water within a few weeks.
Myth: Fingerprint gets removed upon lifting from paper
Fact: There is a possibility of having a print on a porous surface even after lifting as prints get soaked in porous surfaces. And if the powder method is used to lift a fresh print, you can still get some finger marks from that surface.
However, the age of the prints and their stickiness to the surface also matters. But chemical methods like ninhydrin can be used to develop them.
Myth: Fingerprints get removed from the paper on heating
Fact: Here, do not get confused between heating and burning. Both are different. Heating reduces the brightness of the paper leading to tanning. It does not destroy prints but makes them bright and more visible as fats and lipids in the residue start melting, creating contrasting marks on paper.
However, if you heat too much, the paper will burn. Fingerprints can be recorded if the ashes are intact.
Myth: Wiping with bleach destroys fingerprints on paper
Fact: Bleaching does not destroy fingerprints but only disrupts the paper fibers on the surface. Organic compounds like amino acids, fats and lipids get destroyed, but salts and minerals remain. And because of these, fingerprints can still be revealed.
However, if the paper is immersed in the bleaching solution, the paper will get destroyed, destroying fingerprints also.
Myth: Fingerprint development should be done before the Questioned Document examination
Fact: The questioned document should be analyzed for written or printed matter first if it has both writing and fingerprints as the QD examination process is non-destructive.
The primary reason behind it is several times fingerprint development requires applying chemicals that can permanently destroy or stain the document, thereby causing hindrance in its examination.
Also, experts of both departments must coordinate with each other to avoid mishandling.
Myth: Fingerprint marks get destroyed by making an indentation on paper
Fact: Only physical damage is caused by indentation. You cannot erase anything written or printed on the paper by indenting the surface. However, the paper fibers can get destroyed on too much indentation leading to physical damage to the fingerprint area.
Myth: Fingerprint on a paper surface touched by many people is prone to pollution and is of no use
Fact: Paper is made up of cellulose, an excellent medium to hold amino acids for a long time. Also, while committing the crime, the criminal’s excitement level shoots up, multiplying gland secretion levels beyond usual. Hence the amount of material deposited from the culprit’s fingertips is more than that of others. The print shape never gets affected by the pollution even on getting touched by several individuals.
Myth: Exposure to direct sunlight leads the fingerprint to disappear
Fact: The sunlight leads to the evaporation of water and water-soluble molecules. However, solid and non-evaporative materials are not affected, but the naked eye cannot see them. The kind of surface like paper, cotton, textile, banknote, etc., and other conditions also play an essential role in fingerprint development to get satisfactory results.
Myth: Fingerprint is more secure than passwords
Fact: Biometric readers can be prone to vulnerabilities. It is also a technology that can be hacked, leading to the stealing of fingerprints.
The sensitive fingerprint data of civilians and criminals that are digitally stored can be stolen by cybercriminals, just like credit card information and used for illegal activities.
Myth: In the future, passwords will get replaced by fingerprints
Fact: Fingerprints can be copied or stolen, or hackers can bypass biometric readers. Same way, weak passwords can also be hacked. Hence, as per experts, no one security technique is sufficient to protect sensitive information from hackers. It is recommended to have multiple security points like passwords, fingerprints, and other security techniques to access such confidential data.
Myth: Fingerprints can be faked easily
Fact: Though fingerprints can be faked, it is a lot more difficult than your imagination. Every scanner is different, and nowadays, they capture not only the fingerprint but also other features that are enough to differentiate the real from the fake. However, you cannot guarantee 100% accuracy in any manufactured system.
Myth: Fingerprint Evidence is Flawless
Fact: Fingerprints are collected from the crime scene to identify suspects and arrest them if they match the print in the law enforcement database. A poorly trained analyst's comparison of the two prints can result in a mistake. Also, sometimes due to biased decisions, the wrong person gets convicted.
Myth: Fingerprint science is overpowered by DNA fingerprinting
Fact: it is not necessary to find body fluids or blood at the crime scene every time. However, the chances of finding criminals’ fingerprints on the objects are much higher. Hence, apart from fingerprints, no other evidence is known to be so commonly found at the crime scene.
Fingerprint examination is one of the most reliable and important criminal investigation tools.
It is one of the several methods implemented by the forensic investigators to find suspects and convict a criminal.
However, every study is associated with a few doubts or myths I tried to answer here.
Did you enjoy reading it?
Do you know about any other misconceptions related to fingerprint science?
If yes, do share in the comments below.
SIFS India is a government-recognized private forensic science laboratory in Delhi. Our CEO Dr. Ranjeet Singh is a forensic expert of global repute and has successfully delivered his expert services and training internationally.
For about two decades, the training academy has imparted practical hands-on training to thousands of students and shaped the career of aspiring forensic experts.
The certified in-house and guest faculty is at par excellence and has several years of forensics teaching experience.
So, if you want to become a successful fingerprint expert, you must be well-versed in using different fingerprint development techniques and must stay updated about the current development in your chosen domain.
As fingerprint analysis is quite challenging, without proper knowledge and skills, you cannot become successful. Hence in-depth, hands-on training is required for this.
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