Computer Forensic Evidence


            The growing nature of the criminal precepts has seen the growing demand in the development of extensive models of pursuing towards curbing and investigating the ideals of criminality. The contemporary social structures within the global community have persuasively expanded from the bias of the technological advancement that creates ideal procedures and processes for addressing various aspects of societal functions. The methodology and procedures for tracking and addressing criminal offenses are not an exception to this technological boost. However, the great endowment of the computer forensic evidence has perhaps created structural functions that create a strong aspect of criminal investigation and therefore created persuasive models with which these criminal activities can be prompted (Vacca, 2005).

            In recognition of the pragmatic role played by computer forensic evidence, this research paper is therefore a compliment of a detailed analysis and an investigation that employs the incorporation of various domains that enrich the primary aspect of criminality. Through its integrative approach, its focus is therefore able to bring in to light the prospective parameters with which computer forensic evidence is channeled in fingerprinting process.

Computer Forensic evidence

Computer forensic can best be expressed as the application of computer investigation and scrutiny techniques used to congregate evidence apt for presentation in a court of law. The goal of computer forensics is to perform a well thought-out investigation while preserving a documented chain of evidence in order to be able to locate exactly what happened on a computer and who was liable for it. There are some given set of procedures that a forensic investigation should typically follow. After the actual computer has been physically set aside, so as to make sure it is not tainted, the investigators create a digital copy of the hard drive which is then locked away safely. The digital copy is where all the investigations are done (

Investigators use an array of techniques and proprietary forensic appliances to inspect the hard drive copy, searching concealed folders and unallocated disk room for copies of erased, encrypted, or damaged files. Any evidence found on the digital copy is cautiously documented in a report and verified with the original as a basis for preparation for legal proceeding that entail unearthing, depositions, or actual legal action taking place. Computer forensics has developed into its own vicinity of scientific expertise, with supplementary coursework and official recognition.


A fingerprint can best be described as an impression of the friction ridges of the entire or any part of the finger. It can be either a raised portion of the epidermis on the palm, finger and toes or sole skin part, consisting of one or more joined ridge units of friction ridge skin. The term fingerprint usually refers to impressions transmitted from the pad on the last joint of fingers plus thumbs, though fingerprint cards also normally record portions of lower joint regions of the fingers. These are also used to put together identifications (


            Fingerprints were founded on ancient Babylonian clay tablets, seals, and different form of pottery. Some of these fingerprints were put down accidentally by workers during productions, other times it was used as a substitute for signatures. Although the ancient peoples of that time did not recognize that fingerprints could identify individuals, research shows that law officials fingerprinted natives who had been arrested. In China, handprints were used as proof in a trial for theft. The Chinese experts distinguished that fingerprints could also be used as a means of authentication. Furthermore, they noted that no two individuals have could have identical fingerprints (

This principal has been well established throughout the biological sciences of compositions, embryology and heredity. These distinctive anatomical features, which are created prior to birth, are continual throughout one’s life until some period after death. This has become the base upon which the individualization of a fingerprint to a particular person becomes scientifically accepted and legally justifiable.


The exercise of fingerprinting allows crime fighters a tremendously accurate means of identification; this is largely due to its distinct uniqueness as far as ridges are concerned. There are diverse finger print types used for the purpose of identification. Latent prints are accidental impressions left by chafing ridge skin on a surface, in spite of of whether it is visible or invisible at the period of deposition. Electronic, chemical and physical processing techniques allow visualization of invisible latent print remains whether they are from natural secretions of the eccrine glands present on friction ridge skin, or despite the fact that the impression is in a contaminant such as motor oil, blood, paint or ink. Latent print may display only a small portion of the plane of the finger and may be both smudged and unclear, depending on how they were deposited. For these reasons, latent prints are not the best modes to use.

Patent prints are another type of fingerprint. These are friction ridge impressions of unknown origin which are evident to the human eye and are caused by the relocation of foreign material on the finger, onto a surface. As they are already visible, there is no need for their amplification. Therefore, they can be photographed instead of being lifted in the same approach as latent prints. Finger deposits may include materials such as ink, dirt, or blood onto a plane (

Another type of fingerprints is known as the plastic print. This is a friction ridge impression from a finger deposited in a substance that retains the shape of the ridge feature. Examples usually stumbled upon include, melted candle wax, putty detached form the boundary of window panes, along with thick grease deposits on car parts. These types of prints are already visible and need no augmentation therefore can be photographed. However, investigators must not overlook the potential that invisible latent prints left by accomplices might also be on such surfaces. Further attempts should also be made to develop other non-plastic impressions left at natural finger secretions or pollutants.


The validity and effectiveness of forensic fingerprint evidence has in recent times been challenged by scholars, judges as well as the media. While fingerprint identification was a step up over earlier anthropometric organizations, the subjective temperament of matching, along with the relatively soaring error rate of matches when compared to DNA, has rendered this forensic practice controversial. Certain specific criticisms are at present being accepted by a number of leaders of the forensic fingerprint society, providing motivation to improve training in addition to procedures.

Fingerprints gathered at a crime scene, or on bits and pieces of evidence from a crime, can be used in forensic science to spot suspects, victims and other persons who handled a surface. Fingerprint identification materialized as an important system within police agencies in the late 19th century, whilst it replaced anthropometric measurements as a more dependable method for discovering persons having a previous record, often under an assumed name, in an unlawful record repository. The science of fingerprint identification can affirm its reputation amongst forensic sciences for several reasons, including the fact that it has served all government worldwide during the past one hundred years to present precise identification of criminals. No two fingerprints have ever been found identical in numerous billions of human and automated computer assessments. Fingerprints are the very origin for criminal history foundation at every police bureau. Fingerprint identification established the first forensic professional institution called the International Association for Identification, in the year 1915. It also launched the first professional certification syllabus for forensic scientists; the International Association for Identification Certified Latent Print Examiner curriculum which was in charge of issuing certification to those meeting rigorous  criteria and withdrawing certification for serious inaccuracies such as erroneous identifications. In most jurisdictions, fingerprint examination case match remains the most commonly used forensic evidence universally. Fingerprinting continues to expand as the premier techniques for identifying persons, with scores of people added to fingerprint repositories on a daily basis in America alone. This far outstrips similar databases as far as growth is concerned. Fingerprinting is alleged to outperform DNA in addition to all other human identification schemes. It was also the first forensic discipline to officially institute a professional certification program designed for individual experts, not withstanding a procedure for decertifying those building errors. Additional forensic disciplines later followed suit in setting up certification programs whereby certification could be withdrawn for mistakes (

Fingerprint identification effects far more positive identifications of people universally on a daily basis than any additional human identification procedures. Some of the dissatisfaction over fingerprint evidence could be due to the aspiration to push the conclusiveness of fingerprint examinations to the equal level of certainty as that of DNA scrutiny. DNA is probability-based to a great extent is as an individual is genetically half from the mother’s input plus half from the father’s input. These genetic contributions are passed along as of generation to generation. While pattern type may be innate, the details of the friction contours are not. For example, it cannot be said that certain bifurcations of an individual were inherited from their mother and an ending ridge from their father as the development of these characteristics are absolutely random. Furthermore, fingerprints as an analogy of distinctiveness have been widely scientifically acknowledged. For instance, chemists often use the term fingerprint region to illustrate an area of a chemical that can be used to identify it. Another criticism sometimes leveled at fingerprint practice is that it is a closed discipline. Nevertheless, practitioners in the scientific society, asserts that it preserves the need for objectivity and sustained research in the area of friction ridge study (Vacca, 2005).

Case studies

An anecdote that some regard as mythical circulates about events occurring in the early 20th century when a man was spotted in the incoming prisoner line at an American prison by a guard who acknowledged him and thought he was already in the prison inhabitants. Upon examination, the incoming prisoner alleged to be named Will West, whilst the existing prisoner was called William West. According to their Bertillon measurements, they were in actual fact indistinguishable. Only their fingerprints could readily identify them, and the Bertillon method was dishonored. There is evidence that men named Will as well as William West were both imprisoned in that prison. Nonetheless, the details of the case are doubtful, especially since they differ between retells and the tale did not appear in print until 1918. However, the West case is not a case of fingerprint error, but a slip-up in the technique of anthropometry, which the fingerprint science reinstated (

Brandon Mayfield on the other hand was an Oregon lawyer who was identified as a participant in the Madrid bombing based on a purported fingerprint match by means of the FBI. The FBI Latent Print Unit ran the print collected in Madrid furthermore, reported a match against one of 20 fingerprint candidates returned in an investigation feedback from the Integrated Automated Fingerprint Identification System. At first, the FBI said the match was distinguishably positive however, the Spanish police examiners concluded that the prints did not match Mayfield plus two weeks later; another man was matched and convicted. The FBI accepted the miscalculation, and a judge released Mayfield two weeks later. Two years later a report was released that established that misidentification was due to a misapplication of the methodology used by the examiners concerned.

Rene Ramon Sanchez, a lawful Dominican Republic immigrant was booked on a driving under the influence charge on July 15 in the year 1995. He had his fingerprints attached on a card containing the name, social security number and other information for a Leo Rosario, who was being processed at the same point in time. Leo Rosario had been arrested for selling cocaine to an undercover law enforcement officer. In August, 1998, Sanchez was stopped once again by police officers, for driving under the influence, this time in Manhattan. However, he was identified as Leo Rosario and on October 11 of 2000, while coming back from a visit to family members in the Dominican Republic was arrested at Kennedy International Airport. Despite the fact that he did not match the physical portrayal of Rosario, the fingerprints were deemed more reliable. This mistake was owed to an error in clerical processing (

Shirley Mckie was a police detective in 1997 as she was accused of leaving her thumb print inside a house in Kilmarnock, Scotland the same place where Marion Ross had been murdered. Despite the fact that detective Mckie denied having been inside the house, she was arrested in a down raid in 1998; the following year and she was charged with perjury. The solitary evidence was the thumb print supposedly found at the murder scene. Two American experts testified on her behalf at her trail in May 1999 and she was ascertained to not be guilty of the crime. The Scottish Criminal Record Office would not however, admit any error, save for Scottish first minister Jack McConnell who later said there had been an honest mistake. McKie was later compensated despite the controversy that still surrounds this case as to the validity of the ministers’ stand at that time. It was deemed that there had been a mistake in identification (Vacca, 2005).

Stephan Cowans was convicted of attempted murder in the year 1997 after he was accused of the shooting of a police administrator whilst fleeing a robbery in Roxbury, Massachusetts. He was implicated in the crime by the statements of two witnesses, one of the witnesses being the victim. The other evidence was a fingerprint on a glass mug that the attacker drank water from, and professionals testified that the fingerprint did indeed belong to him. He was found guilty and sent to prison with a 35 year sentence. During his time in prison he earned money cleaning up biohazards until he could afford to have the evidence verified for DNA. The DNA did not match his; nonetheless he had already served six years in prison prior to his release. His case was also deemed as an error in identification (

In March 1990, an unidentified assailant sexually molested in addition to fatally stabbing a young woman. At the crime scene, an investigator came up with few leads. The only trace of evidence was a pillowcase, found next to the victim’s dead body, which exhibited many bloodstains. One stain showed some faint fingerprint ridge detail, hardly visible even to the skilled eye. An investigator took the pillowcase to the forensic department’s unit for bloodstain blueprint analysis. Professionals photographed and studied the stains, slowly extracting bit by bit of information. They discovered two things from the analysis; that the many bloodstains came from a knife and that the fingerprint entailed enough ridge detail to carry out a more extensive inquiry. Analysts then sent the evidence to another forensic study center where scientists treated the fingerprint with DFO, a fairly new chemical that turns into fluorescent when unearthed to a light source. Once processed, this presented an improved ridge detail photo.

However, it was still not clear enough. Analysts consequently concluded that the latent was not easily identifiable. A short time later, after attending a demonstration of fingerprint image enhancement conference, they decided to give this technique a shot. Within four hours, the augmentation yielded a more identifiable print. This encouraged the investigators to follow suit with a DNA analysis. The DNA results showed a close match to those on the victim’s pillowcase. During court proceedings, defense attorneys initiated an attack on what they believed to be the most potentially susceptible piece of evidence, the scientific recognition of fingerprint image processing. To counteract, an analyst took the court step by step from beginning to the end of the entire procedure using a full complement of image enhancement paraphernalia. An expert in the field of image processing also offered supporting proof to the court. At the end of the day, the court ruled the enhanced print permissible. Maintenance men working in the defendant’s empty apartment unearthed a military survival knife which was established to contain traces of blood. They matched the ones on the victim’s pillowcase.  Faced with vast evidence including the fingerprint match, the suspect was convicted to four life sentences for murder along with associated offences (

A few years ago, a suspect committing these sorts of crimes would most likely have gone free, due to lack of substantial forensic verifications. Nevertheless, through persistence and by putting to use such modern technologies as finger-print image enhancement, today’s law enforcement investigators can use evidence previously invisible to their predecessors.


Computer Forensic : Siezing the Evidence. Retrieved on 15th October 2008 from              

Computer Forensics in Fingerprinting. Retrieved on 15th October 2008 from

Computer forensics. Retrieved on 15th October 2008 from

Vacca John (2005) Computer Forensics: Computer Crime Scene Investigation. London, Routledge

Zeno’s Forensic Site. Retrieved on 15th October 2008 from