Role of Biometric Analysis in Criminal Investigations

Forensic science is the application of scientific approaches or expertise to matters of criminal and civil law. Due to the broad range of criminal activities, accurate and effective identification has become a crucial requirement for forensic application.

Biometrics is the measurement and statistical assessment of an individual’s distinctive physical and behavioral traits. The first records of biometrics date back to the Babylonian Empire in 500 BC, and the first instance of a biometric identification system was documented in Paris, France, in the 1800s. Alphonse Bertillon developed a method for categorizing and contrasting convicts using precise body measurements. In 1901, the Metropolitan Police in the United Kingdom started the use of biometrics for identification. 

The biometric analysis in criminal investigations is clearly evident in a variety of forensic contexts, including face, fingerprint, iris, voice, handwriting and etc. The various recognition methods used by biometric systems, such as feature extraction, feature robustness, and feature matching make them more effective.

A wide range of applications of biometric analysis for physical and cyber crime detection are currently possible due to the development of forensic biometrics. Additionally, forensic biometrics fills the gaps left by conventional identification methods that relied on individual probability. It is a significant breakthrough in the way perpetrators are detected.

Characteristics of Biometric System

According to Jain et al. (2008), a physical or behavioral trait’s eligibility for use in biometric applications is determined by seven different characteristics.

1. Universality: The attribute must be possessed by every person using the biometric application.

2. Uniqueness: The population’s members must differ sufficiently from one another in order for the trait to be present.

3. Permanence: Over a period of time, the specified biometric feature shouldn’t vary dramatically.

4. Measurability: The characteristic should not inconvenience the person and should be simple to get and digitize. Additionally, it should be capable of being processed further so that features from the acquired data can be obtained.

5. Performance: The limitations set by the individual must be met by the recognition accuracy and the resources used to achieve that accuracy.

6. Acceptability: People who will use the biometric device should be ready to allow the system access to their biometric characteristics.

7. Circumvention: It relates to how simple it is to mimic or copy a person’s behavior using artifacts. The circumvention of the biometric system is supposed to be impossible.

Working of Biometric System

A biometric system works in four stages.

1. Enrollment Unit/Sensor Module: It gathers a person’s unprocessed biometric data in the form of an image, audio, video, or other signal.

2. Quality Assessment and Feature Extraction Unit: The acquired raw data’s quality is initially evaluated. To enhance the quality of the raw data, a signal amplification technique is used. During user enrollment, the extracted feature set is stored in the biometric system as a template and is labeled with the user’s identity. The feature extraction module operates on the biometric signal to extract a salient collection of features to represent the signal.

3. Matching and Decision-Making Unit: This module contrasts the input at hand with the model. When the system verifies the user’s identification, it compares the user’s master template to the new attributes and generates a score or match value.

Multiple match values are produced when a system doing identification compares the new features to the master templates of numerous users. After that, based on a security threshold and matching score, the decision-making unit accepts or rejects the user.

4. System Database Module: The biometric system’s storage is managed by this module. The template obtained from the raw biometric data is kept in the database throughout the enrollment process along with some user biographical details. Afterwards, identification and verification are done.

Applications of Biometrics Analysis in Criminal Investigations

Fingerprint Biometrics

The frictional ridges and valleys on the surface of a fingertip form a unique pattern known as a fingerprint.

After digitalizing or scanning the print taken at a crime scene in order to compare the two prints, and computer algorithms of a biometric system find all the distinctive details and ridge points of the questioned print.

Afterwards, a fingerprint database that has been saved is compared to these distinct feature sets. The Integrated Automated Fingerprint Identification System (IAFIS) offers electronic image storage, automated fingerprint searches, latent searches, and the transaction of fingerprints and responses.

Face Biometrics

A computer-based technology called facial recognition matches a picture or video of a person’s face to a facial biometric database in order to identify them automatically.

The Next Generation Identification - Interstate Photo System (NGI-IPS) and other federal and state facial recognition systems that are authorized for use by the FBI are searched against probe photographs of unknown people to support FBI investigations.

DNA Biometrics

Genetic fingerprinting, commonly known as genetic profiling, is used in DNA biometrics.

In this procedure, the sample’s DNA is first extracted, and it is then fragmented into segments called variable number tandem repeats (VNTRs). The recorded database is then used to compare these segments.

The FBI’s Combined DNA Index System (CODIS) was developed to help laboratories at all levels identify suspects by comparing DNA profiles.

Iris Biometrics

Iris recognition is an automated method of identifying a person based on their distinctive iris pattern.

The pupil and sclera form an annular border around the eye’s iris (white part of the eye). Digital iris templates are compared to templates that have previously been stored during iris recognition.

The UK government uses this to allow visitors to enter the country through a number of British airports using only automatic iris recognition as their only form of identity.

Voice Biometrics

The study of voice biometrics focuses on recognizing speakers based on the people’s voice traits. It is frequently used when voice is the only attribute available for identification.

The voice ID technology from AGNITIO is a vocal biometric tool created for speaker verification by scientific police and criminal identification specialists.

More than 35 countries throughout the world employ it in courts. The biological characteristics that can be recognized in a voice sample of a suspect is measured rather than the actual words.

Conclusion

The benefits of biometric evidence in  law enforcement in present era of digitalization cannot be ignored. And when combined with age-old investigative techniques, the accuracy of the final outcome enhances manifolds.  Its various applications like in fingerprint, face, DNA, iris, and voice analysis plays a major role in criminal investigations. Continuous developments and research will help in further strengthening the reliability of this field.