An impression made on a surface by the pattern of ridges at the ends of fingers and thumbs. No two people have the same fingerprints, and the technique of fingerprinting has thus long been used by law enforcement agencies as a means of identification. Systems of fingerprint classification have been in use since the end of the 19th-c, based on the general shape of the ridge pattern, its size and position on the finger, the number of ridges in loops and whorls, and other such indicators. Computer systems of classification are also now available. The standard process of fingerprinting (dactyloscopy) is one in which the fingers and thumbs are first cleaned, then pressed onto an ink-covered glass surface, then firmly rolled onto a standardized card so as to leave a clear imprint of the full fingertip pattern, so that the ridges may be counted and traced. Genetic fingerprinting is a technique based on the fact that no two persons possess the same patterns of DNA; computerized DNA profiles are therefore now often used as a means of identifying criminals.
A fingerprint is an impression of the friction ridges of all or any part of the finger. A friction ridge is a raised portion of the epidermis on the palmar (palm and fingers) or plantar (sole and toes) skin, consisting of one or more connected ridge units of friction ridge skin.
Fingerprints may be deposited in natural secretions from the eccrine glands present in friction ridge skin (secretions consisting primarily of water) or they may be made by ink or other contaminants transferred from the peaks of friction skin ridges to a relatively smooth surface such as a fingerprint card. The term fingerprint normally refers to impressions transferred from the pad on the last joint of fingers and thumbs, though fingerprint cards also typically record portions of lower joint areas of the fingers (which are also used to make identifications).
Fingerprint identification
Fingerprint identification (sometimes referred to as dactyloscopy) is the process of comparing questioned and known friction skin ridge impressions (see Minutiae) from fingers, palms, and toes to determine if the impressions are from the same finger (or palm, toe, etc.). The flexibility of friction ridge skin means that no two finger or palm prints are ever exactly alike (never identical in every detail), even two impressions recorded immediately after each other. Fingerprint identification (also referred to as individualization) occurs when an expert (or an expert computer system operating under threshold scoring rules) determines that two friction ridge impressions originated from the same finger or palm (or toe, sole) to the exclusion of all others.
Latent prints
Although the word latent means hidden or invisible, in modern usage for forensic science the term latent prints means any chance or accidental impression left by friction ridge skin on a surface, regardless of whether it is visible or invisible at the time of deposition.
Patent prints
These are friction ridge impressions of unknown origin which are obvious to the human eye and are caused by a transfer of foreign material on the finger, onto a surface.
Plastic prints
A plastic print is a friction ridge impression from a finger or palm (or toe/foot) deposited in a material that retains the shape of the ridge detail.
Classifying fingerprints
Before computerization replaced manual filing systems in large fingerprint operations, manual fingerprint classification systems were used to categorize fingerprints based on general ridge formations (such as the presence or absence of circular patterns in various fingers), thus permitting filing and retrieval of paper records in large collections based on friction ridge patterns independent of name, birth date and other biographic data that persons may misrepresent.
In the Henry system of classification, there are three basic fingerprint patterns: Arch, Loop and Whorl.
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Arch |
Right loop |
Whorl |
Tented arch |
Timeline
There is no clear date at which fingerprinting was first used. However, significant modern dates documenting the use of fingerprints for positive identification are as follows:
1823: Jan Evangelista Purkyně, a professor of anatomy at the University of Breslau, published his thesis discussing 9 fingerprint patterns, but he did not mention the use of fingerprints to identify persons. 1892: Sir Francis Galton published a detailed statistical model of fingerprint analysis and identification and encouraged its use in forensic science in his book Finger Prints. 1892: Juan Vucetich, an Argentine police officer who had been studying Galton pattern types for a year, made the first criminal fingerprint identification. He successfully proved Francisca Rojas guilty of murder after showing that the bloody fingerprint found at the crime scene was hers, and could only be hers. 1897: World's first Fingerprint Bureau opens in Calcutta (now Kolkata) India after the Council of the Governor General approved a committee report (on 12 June 1897) that fingerprints should be used for classification of criminal records. Working in the Calcutta Anthropometric Bureau (before it became the Fingerprint Bureau) were Azizul Haque and Hem Chandra Bose. Haque and Bose are the Indian fingerprint experts credited with primary development of the fingerprint classification system eventually named after their supervisor, Sir Edward Richard Henry. 1901: The first United Kingdom Fingerprint Bureau was founded in Scotland Yard. DeForrest used fingerprinting in the New York Civil Service.Reliability of fingerprinting as an identification method
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Fingerprints collected at a crime scene, or on items of evidence from a crime, can be used in forensic science to identify suspects, victims and other persons who touched a surface. Fingerprint identification emerged as an important system within police agencies in the late 19th century, when it replaced anthropometric measurements as a more reliable method for identifying persons having a prior record, often under an alias name, in a criminal record repository.
The science of fingerprint identification stands out among all other forensic sciences for many reasons, including the following:
Has served all governments worldwide during the past 100 years to provide accurate identification of criminals. No two fingerprints have ever been found identical in many billions of human and automated computer comparisons. Fingerprints are the very basis for criminal history foundation at every police agency. Remains the most commonly used forensic evidence worldwide - in most jurisdictions fingerprint examination cases match or outnumber all other forensic examination casework combined. Continues to expand as the premier method for identifying persons, with tens of thousands of persons added to fingerprint repositories daily in America alone - far outdistancing similar databases in growth. Is claimed to outperform DNA and all other human identification systems to identify more murderers, rapists and other serious offenders (fingerprints are said to solve ten times more unknown suspect cases than DNA in most jurisdictions). Fingerprint identification was the first forensic discipline (in 1977) to formally institute a professional certification program for individual experts, including a procedure for decertifying those making errors.On the palmar surface of the hands and feet are raised surfaces called friction ridges. The scientific basis behind friction ridge analysis is the fact that friction ridges are persistent and unique. Even identical twins do not have the same fingerprints. Stochastic effects have widespread scientific acceptance as a source of uniqueness and have been observed in several animal studies which included fingerprint and other unique traits (hair patterning) between both clones and nuclear transfers.
A known print is the intentional recording of the friction ridges, usually with black printer's ink rolled across a contrasting white background, typically a white card. A latent print is the chance reproduction of the friction ridges deposited on the surface of a item, Latent prints are often fragmentary and may require chemical methods, powder, or alternative light sources in order to be visualized.
When friction ridges come in contact with a surface that is receptive to a print, material on the ridges, such as perspiration, oil, grease, ink, etc. Pliability of the skin, deposition pressure, slippage, the matrix, the surface, and the development medium are just some of the various factors which can cause a latent print to appear differently from the known recording of the same friction ridges. Fingerprint identification effects far more positive identifications of persons worldwide daily than any other human identification procedure.
Errors in fingerprint identifications can and do occur. Such errors in fingerprint identification are so rare that when they occur, they normally make headlines worldwide. One of the most famous fingerprint identification mistakes was made by the FBI Laboratory in 2004. Although the FBI Laboratory had previously made about one latent fingerprint identification error each eleven years, the 2004 error was the first instance in the 84 years of the FBI Laboratory's operation when an error was not discovered and corrected before it caused an innocent person to be jailed. Upon investigation by the Office of Inspector General, it was conclusively determined that fingerprint evidence was scientifically reliable. Thus, U.S. courts have upheld fingerprint evidence despite exposure of errors due to the longstanding reliability of the discipline.
Critics of fingerprint evidence have long claimed that practitioners of the field state their conclusions to be "infallible." This is indeed a misquote of the FBI's book "The Science of Fingerprints," which actually dealt with fingerprint classification and not the identification process. Anti-fingerprint activists have gone to great lengths to attempt to cast doubt on the validity of fingerprint evidence, including misleading publications and false testimony.
Much of the discontent over fingerprint evidence is due to the desire to push the conclusion of fingerprint examinations to be more similar to DNA. Further, fingerprints as an analogy of uniqueness has been widely scientifically accepted. For example, chemists often use the term "fingerprint region" to describe an area of a chemical that can be used to identify it.
The other criticism of the fingerprint practice is that it is considered to be a closed discipline. In this respect, fingerprint scientists are no different from the rest of the community. Further, the fingerprint community maintains the need for objectivity and continued research in the area of friction ridge analysis.
For interest, below are examples of fingerprint errors. It should be noted that the exposure of the errors listed below do not mitigate the reliability of fingerprint analysis. Only their fingerprints could readily identify them, and the Bertillon Method was discredited.
There is evidence that men named Will and William West were both imprisoned in the Federal Penitentiary in Leavenworth, Kansas, between 1903 and 1909.
It should be noted that the West case is not is a case of fingerprint error, but an error in the method of anthropometry, which the fingerprint science replaced.
Errors in fingerprint identification or processing
Brandon Mayfield and Madrid bombing
Error in identification. Brandon Mayfield is an Oregon lawyer who was identified as a participant in the Madrid bombing based on a fingerprint match by the FBI. The FBI Latent Print Unit ran the print collected in Madrid and reported a match against one of 20 fingerprint candidates returned in a search response from their Integrated Automated Fingerprint Identification (IAFIS) system. The report also found that the erroneous identification was due to misapplication of the identification methodology by the examiners involved and not a reflection of the reliability of fingerprint evidence.
New York State Police Troop C scandal
Forged fingerprint evidence. In the New York State Police Troop C scandal in April of 1993, Craig D. Harvey admitted he and another trooper lifted fingerprints from items the suspect, John Spencer, touched while in Troop C headquarters during booking. He attached the fingerprints to evidence cards and later claimed that he had pulled the fingerprints from the scene of the murder. Lishansky, of Troop C, admitted they took fingerprints of Ms. He had his fingerprints affixed on a card containing the name, Social Security number and other data for Leo Rosario, who was being processed at the same time. Even though he did not match the physical description of Rosario, the fingerprints were considered more reliable.
Shirley McKie
Error in identification. Shirley McKie was a police detective in 1997 when she was accused of leaving her thumb print inside a house in Kilmarnock, Scotland where Marion Ross had been murdered.
Stephan Cowans
Error in identification. Stephan Cowans was convicted of attempted murder in 1997 after he was accused of the shooting of a police officer while fleeing a robbery in Roxbury, Massachusetts. The other evidence was a fingerprint on a glass mug that the assailant drank water from, and experts testified that the fingerprint belonged to him.
Footprints
Friction ridge skin present on the soles of the feet and toes (plantar surfaces) is as unique as ridge detail on the fingers and palms (palmar surfaces).
Footprints of infants, along with thumb or index finger prints of mothers, are still commonly recorded in hospitals to assist in verifying the identity of infants.
It is not uncommon for military records of flight personnel to include bare foot inked impressions. Even though the U.S. Armed Forces DNA Identification Laboratory (AFDIL) stores refrigerated DNA samples from all current active duty and reserve personnel, almost all casualty identifications are effected using fingerprints from military ID card records (live scan fingerprints are recorded at the time such cards are issued).
US fingerprint databases
The FBI manages a fingerprint identification system and database called IAFIS, which currently holds the fingerprints and criminal records of over fifty-one million criminal record subjects, and over 1.5 million civil (non-criminal) fingerprint records.
Fingerprint compression
Most American law enforcement agencies use Wavelet Scalar Quantization (WSQ), a wavelet-based system for efficient storage of compressed fingerprint images at 500 pixels per inch (ppi). For fingerprints recorded at 1000 ppi spatial resolution, law enforcement (including the FBI) uses JPEG 2000 instead of WSQ.
Fingerprint locks
In the 2000s, electronic fingerprint readers have been introduced for security applications such as identification of computer users (log-in authentication). However, early devices have been discovered to be vulnerable to quite simple methods of deception, such as fake fingerprints cast in gels. In 2006, fingerprint sensors gained popularity in the notebook PC market.
Fingerprints in other species
The Koala is one of the few mammals (other than primates) that has fingerprints. In fact, koala fingerprints are remarkably similar to human fingerprints;
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