Fingerprint In Forensic

Introduction to Fingerprint Analysis

Fingerprint, a term referred for the friction skin on the fingers and the palm from the first joint of the hand to the nail bed. It covers areas of skin bearing ridges and furrows. This includes feet and toes (Gurdoglanyan, 2001).

Friction ridge skin has unique features that persists from before birth until decomposition after death. This feature enables fingerprint as an excellent method for identification (Wertheim, 2011).

The discovery of fingerprints has been made by a scientist back in the 19th century named Francis Galton. He conducted detailed studies and established a system by which these fingerprints were grouped based on ridge patterns. This grouping system has been used as reference in fingerprint analysis (Gurdoglanyan, 2001).

Patterns of Fingerprint

According to Galton’s system, fingerprints are divided into three major classes; 1) arches 2) loops and 3) whorls (Gurdoglanyan, 2001).

1. Arches – this type of fingerprint is identified by a pattern where the ridges enter on one side and exit on the other side of the finger. This class of fingerprint can be further divided into Plain Arch and Tented Arch. Plain Arch is the simplest of all fingerprint patterns. The ridges tend to rise in the center of the pattern, forming a wave-like pattern. The Tented Arch is similar to the Plain Arch. However, there is sharp up-thrust or spike, or the ridges meet at an angle less than 90 degrees.
   

   Arches type fingerprints: Left – Plain Arch, Right – Tented Arch (source: www.sciencespot.net/Media/FrnsScience/Fingerprintbasicscard)

2. Loops – this type of fingerprints are characterized by one or more ridges enter one side and exit the same site the ridge entry, as illustrated below. Loops can be sub-divided into Ulnar Loop (right thumb) and Radial Loop (left thumb).
   

   Loops type fingerprints: Left – Radial Loop, Right – Ulnar Loop (source: http://sciencespot.net//Media/FrnsScience/Fingerprintbasicscard)

3. Whorls – this fingerprint type occurs when at least one ridge makes a complete circuit, as shown below:
   

   Whorl fingerprint type (source: http://sciencespot.net//Media/FrnsScience/Fingerprintbasicscard)

Forensic Application of Fingerprint

In forensic applications, fingerprints can be used for identification because they are 1) unique and 2) permanent.

As explained earlier, fingerprint comprises ridges and furrows forming a unique pattern. On the basis of identification, each fingerprint has a focal point. The core of a fingerprint is a type of focal point.

A fingerprint analyst examines points where the ridges bifurcate, divide into two after being one, or diverge, split apart after running parallel. These points are unique in each individuals making fingerprints an outstanding method for individual identification (Gurdoglanyan, 2001).
Question; where and how the experts obtain these fingerprint impressions? Fingerprint impressions are classified into three basic types; 1) latent print 2) visible print and 3) plastic print (molded).

Latent prints are the most occurring and examined by fingerprint experts. These prints are invisible by naked eyes. Latent prints are formed by sweat, either from the hands themselves or by unconscious contact between the fingers and the face or other parts of the body (Brian Yamashita, 2011).
These ‘hidden’ latent prints can be made visible by dusting an object’s surface suspected to have latent prints. Gray or black powders are two most common dusting materials used to develop latent prints.

Latent print lifting tool consists of a brush, powder and lifting tape (source: thelunchboxseason.com)

Another common method for developing latent prints is cyanoacrylate fuming, using a chemical compound called ninhydrin. Ninhydrin binds with amino acids present in the sweat. This results in the appearance of latent invisible prints within an hour (Brian Yamashita, 2011).

Cyanoacrylate fuming method for developing latent print (source: www.bxscience.edu/publications/forensics/articles/fingerprinting)

In summary, latent fingerprint development may be achieved through various optical, physical, and chemical processes. During the past century, these methods have been evolved and continuously changing. However, the core principal remains the same.

Legal Aspects

‘No two fingerprints are identical’. That is Galton’s proposal where he believed that fingerprints were not inherited and even identical twins had different ridge patterns.
In incriminating a suspect, fingerprinting is indeed a blessing to investigators. It gives them a undisputable means of nailing murderers, thieves and law abusers. Fingerprinting enables a crime to be solved without even one tangible piece of evidence, such as a weapon. It is an amazing tool.

Latent fingerprints are not visible to the naked eye. They can be found anywhere in the crime scene without the criminal even realizing it. It is a foolproof method for Galton proves to us that not one person can have another’s fingerprints; they are as unique as the word unique gets.

Fingerprints, palm prints and bare sole impressions has been recognized and accepted as a method for identifying a person. Thus, the forensic science of fingerprints, palm prints, and footprints is applied by law enforcement agencies in support of their investigations to positively identify the perpetrator of a crime. This forensic science is also used for exculpatory or elimination purposes (Andre A. Moenssens, 2011).

Limitations and Issues

Fingerprint analysis has been accepted as the ‘gold standard’ for human identification because of its uniqueness. In Malaysia, the use of fingerprint examination as the method of human identification is still subject to several limitations. Two issues will be addressed in this article, namely fingerprint experts and immigrants.

1. Qualifications of the Expert Witness

   A witness appointed to offer testimony must first be shown to be qualified as an expert. That step involves the expert taking the stand and being sworn to tell the truth. The most crucial is providing answers to an attorney or a defender relating to his or her competence (Andre A. Moenssens, 2011).

   In our country, the number of expert witness with regard to fingerprint analysis and examination is limited to those trained from The Royal Malaysian Police.

   In Malaysia, The Royal Malaysian Police launched a database called Malaysia Automated Fingerprint Identification System (MAFIS) with collaboration with Jabatan Pendaftaran Negara (JPN). This database stores fingerprints of all Malaysian citizens, and those with criminal records.

   MAFIS requires dedicated specialized team to ensure the database is running efficiently and well updated.

   From the aspect of latent fingerprints development, the techniques and technologies applied in the field keep evolving and demanding new skills. It is important for those experts to polish their skills and keep themselves updated with latest techniques and technologies to avoid from being outdated or old-school. Such negative impressions weaken the strength of an expert witness in the court of law.

2. Immigrants

   ‘Invasion’ of immigrants in our country has been a long debated issue among the citizens and the governing authorities of the country. These immigrants have been known as the contributors of criminal cases in Malaysia. Unfortunately, we don’t have any database to compare and to match those fingerprints that belong to immigrants from the scene of crime.

   Thus, with the long standing reputation of fingerprints as a human identification system, its purpose is not fulfilled without a dedicated, comprehensive database.

   In conclusion, fingerprint identification system has been at its triumph for the purpose of human identification. However, it will remain as the ‘gold standard’ with the well-recognized experts that can stand the test of time.

References

1. Andre A. Moenssens, S. B. M. (2011). Finger Prints and the Law: National Institute of Justice.
2. Brian Yamashita, M. r. (2011). Latent Print Development: National Institute of Justice.
3. Gurdoglanyan, D. (2001). Fingerprints used in Forensic Investigations, from http://www.bxscience.edu/publications/forensics/articles/fingerprinting/r-fing01.htm
4. Wertheim, K. (2011). Embryology and Morphology of Friction Ridge Skin: National Institute of Justice.