Pioneers of Fingerprint Identification

     In 1901 Scotland Yard became the world's first law enforcement agency to routinely fingerprint its arrestees. Fingerprints came to America in 1904 when the St. Louis Police Department established its fingerprint bureau. Before fingerprinting, arrestees in Europe and America beginning in the late 1870s were identified by sets of eleven body measurements, a system created by the Frenchman Alphonse Bertillon. By 1914, the year of Bertillon's death, fingerprinting had replaced anthropometry in every county but the United States where, in several jurisdictions, the outdated and cumbersome identification system stuck around until the early 1920s. Until Alphonse Bertillon and the fingerprint pioneers came up with methods of scientifically identifying criminals, law enforcement remained in the dark ages. For this reason Alphonse Bertillon is considered one of the founding fathers of modern policing.

     Beyond the use of fingerprint science to maintain and classify arrest records, and to identify arrestees who are wanted in other jurisdictions, crime scene fingermarks, so-called latent fingerprints, constitute one of the most common forensic techniques of linking suspects to the sites of their offenses. While latent prints can be made visible by various chemicals, iodine fuming, superglue fumes and laser technology, the most common method of bringing out and preserving this type of crime scene evidence, particularly on hard surfaces, involves the application of a fine powder and lifting tape. (This explains the phrase, the latent was lifted from the scene.)

     In 1911 a  Chicago judge, in a first of its kind case, allowed a latent fingerprint into evidence as proof of the defendant's guilt. Since then crime scene latent fingerprint identifications have sent tens of thousands of criminals to prison. The beauty of crime scene fingerprint examination involves the fact it doesn't take high technology or great skill and education to recover this form of trace evidence. Moreover, the comparison of crime scene latents and known fingerprints does not require an advanced degree in science. Jurors can look at a courtroom exhibit in the form of side-by-side enlarged photographs of the two prints depicting their points of joint identify. Unlike DNA identification which requires a leap of faith in science, the matching of a known and unknown fingerprint simply requires good eyesight and faith in the integrity of the evidence. (There have been, however, lapses in the fingerprint integrity aspect of latent fingerprint identification.)

     Today, crime scene latents can be fed into a supercomputer--the Automated Fingerprint Identification System (AFIS)--and matched with single, digitized fingerprints stored in the computer's massive data base. Identifying unknown crime scene latents this way is one of the few instances where forensic scientists can solve and prove cases. When AFIS became operational in the late 1980s crusaders for the professionalization of criminal investigation and the increased use of forensic science in crime solving envisioned the dawn of a new era in law enforcement much like the introduction of fingerprint science at the beginning of the Twentieth Century.

     America's forensic science pioneers of the early Twentieth Century hoped for a future in which the police would defeat crime through latent fingerprint identification and other forms of forensic science. These early crusaders for scientific crime investigation could not have foreseen how the war on drugs would drain law enforcement resources away from forensic science and criminal investigation. These men would have been shocked and dismayed by the low status and poor results of crime solving in modern law enforcement. 

The Madrid Bombing Case: Fingerprint Misidentification

     On March 11, 2004, terrorists in Madrid Spain bombed a passenger train, killing 191 people. The Spanish National Police sent the FBI digital images of eight latent prints found at the bomb site. These images were fed into the FBI's Integrated Automatic Fingerprint Identification System (IAFIS), a $640 million supercomputer housed in Clarksburg, West Virginia. The computer selected from its collection of 48 million fingerprints sets, 15 digital latent images as possible matches. Three FBI examiners matched one of the 15 possibles to a latent from Spain that had been left on a plastic bag containing bomb detonators. The FBI experts believed this print belonged to a 37-year-old lawyer from Portland, Oregon named Brandon Mayfield.

     If the FBI fingerprint experts were correct, Brandon Mayfield had been at the scene of the Madrid bombing. The fact that Mayfield, a former Army lieutenant who had converted to Islam heightened the FBI's suspicion that he had been involved in the deadly bombing.

     Fingerprint examiners in Spain agreed that Mayfield's print and the crime scene latent shared eight points of similarity, but the numerous dissimilarities kept them from declaring a match. The FBI responded by having a fourth bureau expert look at the evidence, and he too, declared a match. Shortly thereafter, FBI agents arrested Brandon Mayfield. In the meantime, the police in Spain announced that the crime scene latent belonged to an Algerian suspect named Ouhane Daoud.

     A team of FBI fingerprint experts traveled to Madrid and when they compared Mayfield's fingerprint to the actual latent they realized their mistake. Blaming the misidentification on the low-resolution image of the digital print, the FBI apologized to Mr. Mayfield. However, when a panel of fingerprint experts reviewed the evidence, they found that the misidentification had nothing to do with the quality of the digitized latent. The four FBI experts had simply overlooked easily observed dissimilarities between the two prints.They allowed their eagerness to identify a terrorist override their scientific objectivity. There may also have been an element of groupthink in the misidentification.

     Brandon Mayfield filed a lawsuit, and in November 2006, the federal government agreed to pay him $2 million in damages. The Justice Department augmented the settlement with an official apology, stating that misidentifications of this nature were rare. University of California at Irvine professor Simon Cole disagreed. Responding to news of the settlement, he told a Los Angeles Times journalist that "this is a tip-of-the-iceberg phenomenon. The argument has always been that no two people have fingerprints exactly alike. But that's not what you need to have an error. What you need is for two people to have very similar fingerprints and that's what happened here."

    For years, when FBI experts testified in criminal trials they claimed that in the history of the bureau there had never been a fingerprint misidentification. They could no longer make this claim which was never true. Moreover, in the wake of the Madrid bombing case embarrassment, the FBI fingerprint examiner proficiency test came under attack. According to a FBI whistleblower, if the test was not so ridiculously easy,cheating would be commonplace.

     While juries and the American public believe deeply in the reliability of fingerprint identification, it is not hard science, and there will be identification mistakes.

The Early History of Fingerprints

     The ancient Chinese had recognized the potential of fingerprints, sealing their documents with thumbprints by way of a "signature." An English naturalist, Thomas Bewick, used wood-block engravings of his own fingerprints as an imprint on the books he published. In the early nineteenth century, a Czech physiologist called Purkinje set out a description of the nature of fingerprints and classified various kinds. But it wasn't until 1880 that an expatriate Scottish physician, Dr. Henry Faulds, living in Japan, first recognized their forensic potential, suggesting that fingerprints found at the scene of a crime could lead to the conclusive identification of the culprit.

     Fauld's idea led to the publication in 1892 of the scientific exploration of fingerprints by Dr. Francis Galton. This in turn prompted Englishman Edward Henry and an Argentinian researcher Juan Vucetich to develop more sophisticated classification systems for fingerprints. [They were grouped into arches, loops and whorls. In 1901, Scotland Yard began collecting fingerprints from arrestees. In 1906, the St. Louis Police Department became the first U.S. law enforcement agency to start a fingerprint bureau. Many American police agencies didn't adopt fingerprinting until the 1920s.] 

Roger Wilkes, ed, The Mammoth Book of Murder & Science, 2000

History of Fingerprint Testimony

As finger print evidence is comparatively new, difficulty is frequently experienced in convincing a jury that the testimony of finger print experts is competent and positive evidence.

Frederick Kuhne, The Fingerprint Instructor, 1916

Jekyll and Hyde Have the Same Fingerprints

Jekyll's finger patterns remain the same when he transforms himself into Hyde.

Henry Faulds (l843-1930) English fingerprint pioneer 

Crime Scene Fingerprints

Just because a person touches something doesn't necessarily mean he or she has left behind a latent print. Not all surfaces are receptive to finger marks. For example, it is particularly difficult to retrieve a latent print from rough-surface wood, cloth, skin, cardboard, and Styrofoam. Finger marks can also be incomplete (called partials), smudged, smeared, or on top of each other. Smooth, shiny surfaces are the best sources for clear, complete latents suitable for comparison and identification. At the crime scene, these latents can be brushed with a fine powder and lifted from the surface with strips of transparent tape. It is not a perfect process and can be a hit-and-miss proposition. Ideally, removable objects that may contain the perpetrator's latents--drinking glasses, bottles, cans, guns, cigarette butts, knives, shell casings and the like--are best sent to the crime lab where special equipment and techniques can make the marks visible for expert analysis. The same goes for grocery bags, sheets of paper, envelopes, notebooks, and magazines that might carry latent prints. Finger marks on countertops, furniture, doorknobs, cellphones, automobiles and window glass are usually lifted at the scene. Latents that can be seen by the naked eye--for example, prints in safe insulation dust, blood, wet paint or soot--should be photographed where they are found.

Worn Down Fingerprints

People who do manual labor, such as construction work, have long been known for wearing down their fingerprints…Many other occupations also have a similar effect, although for different reasons. Musicians such as guitarists can abrade their prints into oblivion; typists may wear them down from so much keyboarding. Even surgeons sometimes rub off their prints from washing their hands repeatedly. The fingerprints don't disappear permanently, but they may not be recognized by biometric access control devices based on fingerprint identification. [Criminals with worn down finger ridges may also leave behind less defined latent prints at crime scenes.]

Marilyn Savant, Parade, December 7, 2014 

Challenging the Fingerprint Expert

     During the first ninety years of fingerprint history, defense attorneys whose clients' latent fingerprints were found as the scenes of crimes had one option--plead them guilty in return for a lighter sentence. No one considered questioning the credibility or competence of a fingerprint expert, and no one dared challenge the scientific reliability of fingerprint identification. Fingerprints either matched or they didn't. There was nothing to challenge.

     Those days are over. Since 2000, there have been numerous cases of latent fingerprint misidentification in the United States and Europe. As it turns out, many fingerprint experts in the United States are undertrained, dishonest, and biased in favor of the police. Most of the nation's competent examiners are overworked due to crime lab budget cuts. Today, it is not unusual for a criminal trial to feature dueling fingerprint experts. This is bad for forensic science and the criminal justice system.   

Thawing Latent Fingerprints

     We got a call. There had been a break-in and a murder of a man in his cabin. This was in the North Woods; there were still some cabins up there without electricity. We went up there, and it was about ten or twenty degrees below.

     The first thing we had to do was build a fire in the old wood stove to get the cabin up to heat. When it's that cold, you can't do any latent fingerprint processing. The reason is, if you put a fingerprint down in freezing temperature, the moisture you transfer, perspiration, is going to freeze. And the fingerprint powder will not stick to the print. It'll run right off. You basically need a little bit of humidity in the air to process latent prints. If it's cold, you warm the area up, and what your doing is, you're thawing the fingerprint out.

     We spent the first five hours at the scene building a fire and warming the place up just so we could go through and process the cabin for fingerprints.

Crime Scene Investigator in Connie Fletcher's, Crime Scene, 2006