Fingerprint Analysis in Forensic Science – An Overview

Have you ever noticed the lines present on your palms? There are some short lines while there are some longer lines as well. Some seem lighter on the hands while some are darker and deeper. These variations in the print lines on your palm make a distinction in people. These prints are known as fingerprints and are unique features of each individual on this earth. You must be amazed to know that two identical twins might have the same DNA but don’t have identical fingerprints. This uniqueness in fingerprints of all individuals is the main reason for the use of fingerprint analysis in crime investigations by forensic scientists.

Forensic Examiners use fingerprint analysis to check the background of people involved in a civil or criminal case, identification of people who died or missing due to an accident, etc. For more than 100 years, fingerprints have been used by investigators to help law enforcement agencies in crime solving. One of the most important features of using fingerprint analysis is that it enables investigators to trace criminals by using previous records. It is because of these prints that police personnel and crime investigation departments are able to figure out whether the same person is involved in two different cases at different places or not.

What is Fingerprint Analysis?

You must be curious to know how investigators use fingerprints to solve crime mysteries. Let us tell you, that this is done through a scientific technique of forensic science known as fingerprint analysis. The comparison of fingerprints found at crime scenes with fingerprints of people involved in a crime either as a criminal or as a victim to identify whether two prints match or not is known as fingerprint analysis. The fingerprint examiners analyze the shapes and lengths of these lines to make comparisons. Fingerprints that are collected from a crime site are known as latent prints and are found to be smudged or distorted. 

Who Conducts Fingerprint Analysis?

The analysis and examination of fingerprints are done by forensic scientists and examiners after years of training and experience in the relevant field. The fingerprint analysis is done through a set of scientific techniques and uses various algorithms to conduct searches. The examiners review the prints collected from the crime spot, evidence found at the scene, and people associated with the crime and conclude the case findings.

The people who conduct investigations on these prints are known as fingerprint experts and require a bachelor’s or a master’s degree in forensic science with relevant experience. Such candidates can pursue B.Sc., B.Tech, M.Sc., or M.Phil to conduct research and help the crime investigators to solve the case and held the offender accountable for what he did.

How is Fingerprint Analysis Done?

To conduct the analysis of fingerprints, the experts first visit the crime scene and collect all the prints right from comb to glasses. After the successful collection of these prints from the objects present at the crime scene, the experts examine these prints and compare them with the earlier records present in the database. The analysis is done at forensic laboratories where such experts examine the prints to get the required information about the case. These examiners use a loupe to examine each minute detail of the print. To give you a better understanding of the same here we have given the detailed process involved in the analysis of fingerprints:

Process of Fingerprint Analysis:

The examination and analysis of the prints is not an easy task and demands the full attention of the examiner. It is a detailed process that has several steps that need to be followed by the forensic examiners. The main principle behind the analysis of prints is to figure out the disparities in the print so that it can be used for comparison. In cases where the prints are not enough to predict the person involved in the crime then the print is declared unsuitable for investigation purposes and another way for finding the criminal is analyzed.

And in cases where the prints are visible enough that they can predict the people involved in the case then the features of the prints are used to figure out the physical features like creases, scars, deltas, etc. To examine these prints these professionals use the famous ACE-V method, commonly known as analysis, comparison, evaluation, and verification.

In order to compare the prints, the examiners view the prints found as evidence along with the prints of suspects simultaneously. These experts compare each minute feature of the fingerprint to conclude whether the two prints match or not. Once an examiner concludes his findings on the case, his findings are verified by another examiner to determine whether the reports are correct or there is any discrepancy in the report.

Principles Used In Fingerprint Analysis:

Do you know what makes your fingerprints unique and different even from your identical twin? Things that make a difference in the prints of each individual are the lines present on your palm known as furrows and ridges. These lines are present on your fingers, palms, and toes and create unique patterns and forensic experts rely on these patterns to analyze the prints and help in the crime investigation.

To get a clear picture of these patterns, forensic scientists have classified them under the following groups:

• Loops:The patterns on your palm that form loops and curves are known as loops. These patterns can be further classified into radial and ulnar loops. Radial loops are the ones that point towards your thumb while ulnars are the ones that point towards your ulna bones. Let us tell you that 60% of the fingerprints are made of loop patterns.
• Whorls:These patterns are circular in shape and often viewed as whirlpools hence called whorls. These patterns can be plain or concentric in shapes which are a central pocket loop with a whorl at one end and a double loop or accident loops that are irregular in shape. These patterns make up 35% of an individual’s fingerprints.  
• Arches:These are wave-like patterns that consist of plain and bent arches that rise to a higher point compared to plain arches. 5% of the fingerprints are made up of arches.
• Persistent patterns: The most reliable fingerprints that are considered for criminal investigation over the years are persistent patterns. These patterns do not change throughout the life of a person. In cases where the skin is damaged the new skin also follows the existing patterns and forms ridges and furrows on the same patterns.

Types of Fingerprints:

The impressions of your hands, known as fingerprints are found on every solid surface someone touches. The fingerprints can be traced on the human body as well. Depending on the visibility and type of surface prints found, these prints are classified into three categories namely:

• Latent Prints: These prints are the body’s natural oils and sweat deposited on another surface. These prints are present widely and can be found on a variety of surfaces. The detection of these prints requires several methods for identification for example, charcoal powder, chemical agents, light sources, etc.
• Patent Prints: These prints can be found on smooth, rough, porous, and non-porous surfaces like paper, cloth, wood, metal, glass, plastic, etc.
• Plastic Prints: These prints are found on soft surfaces like soap, wet paint, wax, fresh caulk, etc.

ACE-V in Fingerprint Analysis:

The fingerprint analysis process for latent prints is known as ACE-V (Analysis, Comparison, Evaluation, and Verification). This is one of the most important analysis methods used in the examination of fingerprints. Let us tell you in detail about this process:

• Analysis:The first step of ACE-V is the print analysis. In this step, the prints collected from a crime site and the evidence found at the scene are compared with the suspected areas to get proper clarity of print along with other important details. 
• Comparison:In this step of the print analysis the fingerprint and palm prints connected with the crime mystery are compared with the listed/sample print of suspects of the case and the victims. 
• Evaluation:Once the comparison of prints is completed now the next step is to examine the similar and variable points of both the prints collected for the purpose of examination.
• Verification:After all the above steps are completed by the main examiner appointed for the case and concludes his findings on the case, another senior examiner now analyzes the prints collected and the findings of the examiner and thus gives his opinion, on whether the findings are correct or need some changes. 

Limitations of Fingerprints Analysis:  

Since we know no method is perfect and has limitations to some extent the same thing is followed in this method of crime investigation as well. When an investigator collects the sample of prints from the suspects or the people connected with the crime in any manner it is not important that the data of the same prints must be present in the past records that the investigator is searching for.

When we talk of variation in the fingerprints of all the individuals present on this earth, we should understand how delicate it is to handle these prints because a minute variation in prints can change the entire case and findings. Thus it is important to take care of these prints and be cautious while dealing with them.

When the examiners investigate latent prints, they must make sure that the prints are held under controlled weather. It’s because latent prints are affected by the weather, if the weather is hot then the prints will be drowned because of perspiration. If the weather is cold, then the prints will not be recorded on the objects nearby because of less availability of moisture. The rain and wind will also cause variation in the prints either they will fade away because of rain water or the wind will bring small particles sticking to these prints hence making variations in the findings.

Fingerprint analysis is a tough task and hence requires the examiner to pay his full attention to get the required result of the examination. These prints play an important role in the crime investigation since they work in such situations also where there is no hope of finding any suspect.

References:

• https://www.forensicsciences implified.org/prints/
• https://www.nist.gov/forensic- biometrics#:~:text=Fingerprint%20analysis %20generally%20involves%20comparing, assessing%20how%20similar%20they%20are.
• https://www.azolifesciences.com /article/Fingerprint-Analysis-in- Forensic-Science.aspx
• https://www.forensicsciences implified.org/prints/how.html
• https://www.fingerprintexpert.in /blog-details/fingerprint-analysis -and-examination