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Fingerprint

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This article is about human fingerprints. See also Fingerprint (disambiguation).

The tip of a finger showing the friction ridge structure. The fingerprint created by that friction ridge structure.

A fingerprint is an impression of the friction ridges of all or any part of the finger.<ref name=swglos>Peer Reviewed Glossary of the Scientific Working Group on Friction Ridge Analysis, Study and Technology (SWGFAST)</ref> 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.<ref name=swglos /> These ridges are sometimes known as "dermal ridges" or "dermal papillae".

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.<ref name= olsen1>Olsen, Robert D., Sr. (1972) “The Chemical Composition of Palmar Sweat” Fingerprint and Identification Magazine Vol 53(10)</ref> 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).

Contents

[edit] Fingerprint identification

Fingerprint identification (sometimes referred to as dactyloscopy<ref name=ashbaugh1>Ashbaugh, David R. (1991) "Ridgeology". Journal of Forensic Identification Vol 41 (1) ISSN: 0895-l 73X</ref>) 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.

[edit] 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. Electronic, chemical and physical processing techniques permit visualization of invisible latent print residue whether they are from natural secretions of the eccrine glands present on friction ridge skin (which produce palmar sweat, sebum, and various kinds of lipids), or whether the impression is in a contaminant such as motor oil, blood, paint, ink, etc.

[edit] 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. Because they are already visible they need no enhancement, and are photographed instead of being lifted.<ref name= swglos />

[edit] 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.<ref name=lifeoflatents>Johnson, P. Lee (1973) "Life of Latents" Identification News Vol 23(1)</ref> Commonly encountered examples are melted candle wax, putty removed from the perimeter of window panes and thick grease deposits on car parts. Such prints are already visible and need no enhancement, but investigators must not overlook the potential that invisible latent prints deposited by accomplices may also be on such surfaces. After photographically recording such prints, attempts should be made to develop other non-plastic impressions deposited in natural finger/palm secretions (eccrine gland secretions) or contaminates.

[edit] 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. The most popular ten print classification systems include the Roscher system, the Vucetich system, and the Henry system. Of these systems, the Roscher system was developed in Germany and implemented in both Germany and Japan, the Vucetich system was developed in Argentina and implemented throughout South America, and the Henry system was developed in India and implemented in most English-speaking countries.<ref name=roscher>Engert, Gerald J. (1964) "International Corner" Identification News Vol 14(1)</ref>

In the Henry system of classification, there are three basic fingerprint patterns: Arch, Loop and Whorl.<ref name= henryclass>Henry, Edward R., Sir (1900) Classification and Uses of Finger Prints London: George Rutledge & Sons, Ltd.</ref> There are also more complex classification systems that further break down patterns to plain arches or tented arches.<ref name=roscher /> Loops may be radial or ulnar, depending on the side of the hand the tail points towards. Whorls also have sub-group classifications including plain whorls, accidental whorls, double loop whorls, and central pocket loop whorls.<ref name= roscher />

Arch
Right loop
Whorl
Tented arch

[edit] 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:

[edit] Reliability of fingerprinting as an identification method

Image:Measuring fingerprints w compass RCMP.jpg

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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.<ref name= ashbaugh1 />

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.<ref name= ashbaugh1 />
  • Established the first forensic professional organization, the International Association for Identification (IAI), in 1915.<ref name= iaihist>International Association for Identification History, retrieved Aug 2006</ref>
  • Established the first professional certification program for forensic scientists, the IAI's Certified Latent Print Examiner program (in 1977), issuing certification to those meeting stringent criteria and revoking certification for serious errors such as erroneous identifications.<ref name= lpcb1>Bonebrake, George J. (1978) "Report on the Latent Print Certification Program" Identification News Vol28(3)</ref>
  • 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. Other forensic disciplines later followed suit in establishing certification programs whereby certification could be revoked for error.<ref name= lpcb1 />

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. Friction ridges are formed during fetal development where their unique characteristics emerge due to genetic and epigenetic factors (maternal diet, pH, temperature, movement of the fetus, etc). Even identical twins do not have the same fingerprints. Uniqueness among even identical twins is due to random, or stochastic, effects during fetal development. 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. Friction ridges also persist throughout life in their permanent arrangement barring scarring or injury or until decomposition of the skin following death. Scarring occurs due to damage to the basal layer of the epidermis. Like friction ridges, scars are also persistent throughout life and are re-generated in new layers of skin.

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. Friction ridges can also be recorded digitally using a technique called Live-Scan. 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. can be transferred to the item. The factors which affect friction ridge impressions are numerous, thereby requiring examiners to undergo extensive and objective study in order to be trained to competency. 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. Indeed, the conditions of friction ridge deposition are unique and never duplicated. This is yet another reason as to why extensive and objective study is necessary in order to train examiners to be able to reach competant conclusions. 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.[citation needed] 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,[citation needed] 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.[citation needed] 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. Most of the anti-fingerprint activists are attorneys or academics (in non-science fields such as "Science & Technology Studies".

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. DNA is probability based due to the fact that an individual is genetically half of the mother's contribution and half the father's contribution. These genetic contributions are passed down from generation to generation. While pattern type (arch, loops, and whorls) may be inherited, the details of the friction ridges are not. For example, it cannot be concluded that that a person inherited a certain bifurcation from their mother and an ending ridge from their father as the development of these features are completely random. 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. Again, this criticism is by non-scientists who fail to understand that practitioners in the scientific community are generally specialized and may not expand to other areas of science. 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.

[edit] William West

A story that some regard as apocryphal circulates about events occurring in the early 20th century when a man was spotted in the incoming prisoner line at the U.S. Penitentiary in Leavenworth, Kansas by a guard who recognized him and thought he was already in the prison population. Upon examination, the incoming prisoner claimed to be named Will West, while the existing prisoner was named William West. According to their Bertillon measurements, they were essentially indistinguishable. 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. However, the details of the case are suspicious, especially since they differ between retellings, and the story did not appear in print until 1918. Today, people familiar with the story differ on whether the story was accurate, a case of people (possibly separated twins) who bore a striking resemblance, a case of known twins, or complete fiction. The story of Will West is mentioned on page 167 of Forensic Uses of Digital Imaging by John C. Russ, with mug shots of "the two Will Wests" on page 168.

It should be noted that the West case is not a case of fingerprint error, but an error in the method of anthropometry, which the fingerprint science replaced.

[edit] Errors in fingerprint identification or processing

Below are cases of errors in fingerprint identification; however, some cases involved misfiling of fingerprints or suspect profiling which slanted interpretation, rather than faults by objective matches from fingerprint search technology.

[edit] Brandon Mayfield and Madrid bombing

Error in identification (of a convert to Islam): Brandon Mayfield is an Oregon lawyer who was identified as a participant in the Madrid bombing based on a so-called fingerprint match by the FBI. <ref name=MayfieldNYT> 

   "U.S. Will Pay $2 Million to Lawyer Wrongly Jailed - New York Times" (article),
   by Eric Lichtbau, New York Times, 2006-11-30, webpage:
   NYT-061130-settle:
   on Brandon Mayfield mistaken arrest.

</ref> 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 FBI initially called the match "100 percent positive" and an "absolutely incontrovertible match". The Spanish National Police examiners concluded the prints did not match Mayfield, and after two weeks identified another man who matched. The FBI acknowledged the error, and a judge released Mayfield after 2 weeks in May 2004.<ref name=MayfieldNYT/> In January of 2006, a U. S. Justice Department report was released which faulted the FBI for sloppy work but exonerated them of more serious allegations. The report found that misidentification was due to misapplication of methodology by the examiners involved: Mayfield is an American-born convert<ref name=MayfieldNYT/> to Islam and his wife is an Egyptian immigrant,<ref name=MayfieldNYT/> not factors that affect fingerprint search technology.

On 29 November, 2006, the FBI agreed to pay Brandon Mayfield the sum of US$2 million.<ref name=MayfieldNYT/> The judicial settlement allows Mayfield to continue a suit regarding certain other government practices surrounding his arrest and detention. The formal apology stated that the FBI, which erroneously linked him to the 2004 Madrid bombing through a fingerprinting mistake, had taken steps to "ensure that what happened to Mr. Mayfield and the Mayfield family does not happen again." <ref name=MayfieldNYT/>

[edit] 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, a New York State Police trooper was charged with fabricating evidence. 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. The forged evidence was used during trial and John Spencer was sentenced to 50 years to life in prison. Another fabrication involved the 1989 murders of the Harris family of Dryden, New York. In their home, Warren and Dolores Harris, their daughter, Shelby, 15, and their son, Marc, 11, were bound and blindfolded, Shelby was raped and sodomized, all four were shot in the head and the house was doused with gasoline and set afire. State police investigators say that evidence led them to Michael Kinge, and that officers killed him when he pointed a shotgun at them during the arrest. His mother, Shirley Kinge, admitted to using a credit card stolen from the Harris home. Officers David L. Harding and Robert M. Lishansky, of Troop C, admitted they took fingerprints of Ms. Kinge from her work place and claimed to have found them on gasoline cans found at the Harris home. She was convicted of burglary and arson and sentenced to 17 to 44 years in prison. She served two and a half years before it was revealed that she had been framed by the police. Her conviction was later overturned.<ref>New York Times; February 4, 1997; "Supervision of Troopers Faulted In Evidence-Tampering Scandal. Concluding a four-year investigation into the worst scandal in state police history, a special prosecutor said today that troopers were able to plant evidence routinely in criminal cases across a broad swath of rural New York because they had no fear of detection by supervisors, who maintained a willful ...</ref>

[edit] Rene Ramon Sanchez

Error in "Clerical" processing. Rene Ramon Sanchez, a legal Dominican Republic immigrant was booked on a DUI charge on July 15, 1995. 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. Leo Rosario was arrested for selling cocaine to an undercover police officer. In August of 1998, Sanchez was stopped again by police officers, for DUI in Manhattan. Rene was then identified as Leo Rosario on October 11, 2000, while returning from a visit to relatives in the Dominican Republic. He was arrested at Kennedy International Airport. Even though he did not match the physical description of Rosario, the fingerprints were considered more reliable.<ref> New York Times; May 31, 2004; Can Prints Lie? Yes, Man Finds To His Dismay. In front of the immigration judge, the tall, muscular man began to weep. No, he had patiently tried to explain, he was not Leo Rosario, a drug dealer and a prime candidate for deportation. He was telling the truth. He was Rene Ramon Sanchez, an auto-body worker and merengue singer ...</ref>

[edit] 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. Although detective constable McKie denied having been inside the house, she was arrested in a dawn raid the following year and charged with perjury. The only evidence was the thumb print allegedly found at the murder scene. Two American experts testified on her behalf at her trial in May 1999 and she was found not guilty. The Scottish Criminal Record Office (SCRO) would not admit any error, but Scottish first minister Jack McConnell later said there had been an "honest mistake".

On February 7, 2006, McKie was awarded £750,000 in compensation from the Scottish Executive and the SCRO.[1] Controversy continues to surround the McKie case with calls for the resignations of Scottish ministers and for either a public or a judicial inquiry into the matter.[2]

[edit] 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. He was implicated in the crime by the testimony of two witnesses, one of which was the victim. 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. He was found guilty and sent to prison with a sentence of 35 years. While in prison he earned money cleaning up biohazards to accrue enough money to have the evidence tested for DNA. The DNA did not match his, he had already served six years in prison before he was released.

[edit] 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). When recovered at crime scenes or on items of evidence, sole and toe impressions are used in the same manner as finger and palm prints to effect identifications. Footprint (toe and sole friction ridge skin) evidence has been admitted in U.S. courts since 1934 (People v. Les, 267 Michigan 648, 255 NW 407).

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. Often, the only identifiable ridge detail in such impressions is from the large toe or adjacent to the large toe, due to the difficulty of recording such fine detail. When legible ridge detail is lacking, DNA is normally effective (except in instances of chimaerism) for indirectly identifying infants by confirming maternity and paternity of an infant's parents.

It is not uncommon for military records of flight personnel to include bare foot inked impressions. Friction ridge skin protected inside flight boots tends to survive the trauma of a plane crash (and accompanying fire) better than fingers. 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). When friction ridge skin is not available from deceased military personnel, DNA and dental records are used to confirm identity.

[edit] U.S. 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. U.S. Visit currently holds a repository of over 50 million persons, primarily in the form of two-finger records (by 2008, U.S. Visit is transforming to a system recording FBI-standard tenprint records).

[edit] 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). WSQ was developed by the FBI, the Los Alamos National Lab, and the National Institute for Standards and Technology (NIST). For fingerprints recorded at 1000 ppi spatial resolution, law enforcement (including the FBI) uses JPEG 2000 instead of WSQ.

[edit] 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. Built-in sensors in ThinkPads, VAIO laptops, and others also double as motion detectors for document scrolling, like the scroll wheel.

[edit] 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; even with an electron microscope, it can be quite difficult to distinguish between the two.<ref>Henneberg, Maciej, Lambert, Kosette M., Leigh, Chris M. (1997). "Fingerprint homoplasy: koalas and humans". naturalSCIENCE.com 1.</ref>

[edit] See also

[edit] References

<references />

[edit] External links

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ar:بصمة cs:Daktyloskopie de:Fingerabdruck es:Huella dactilar fr:Empreinte digitale gl:Pegada dactilar hr:Daktiloskopija id:Sidik jari he:טביעת אצבע nl:Dactyloscopie ja:指紋 no:Fingeravtrykk pl:Linie papilarne pt:Impressão digital (anatomia) ru:Дактилоскопия sk:Daktyloskopia sl:Prstni odtis sv:Fingeravtryck tr:Parmak izi zh:指紋

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