The Pioneers: Locard, Bertillon, Galton, Lattes, Gross

Hans Gross (1847-1915) spent his career as an examining magistrate in Graz, Austria, and later as a professor of criminal law. He was frustrated throughout his early career by the gap between the physical evidence that investigators found at crime scenes and the ability of judges and lawyers to understand what that evidence meant. His response was to write what became the first comprehensive textbook of forensic science.

Published in 1893 as Handbuch fur Untersuchungsrichter (Handbook for Examining Magistrates), the book covered every technique then available for investigating crime: fingerprints, microscopy, blood analysis, soil examination, ballistics, questioned documents, anthropometry, photography, and the chemistry of poisons. Gross drew on the best contemporary science and translated it into practical guidance for investigators who were not scientists. The book ran to multiple editions, was translated into English, French, Russian, and other languages, and is still cited as the founding text of academic criminology and criminalistics.

Gross also coined the term Kriminalistik for the integrated scientific discipline of crime investigation, distinguishing it from criminology (the study of criminal behaviour) and from forensic medicine (the medical aspects of legal proceedings). This terminological clarity mattered. By naming the discipline, Gross made it possible to argue that it deserved universities, laboratories, and trained practitioners, not just occasional expert witnesses hired by lawyers.

Alphonse Bertillon (1853-1914) arrived at the Paris Prefecture of Police in 1879 as a records clerk, frustrated by the disorganised way criminal records were kept. The problem he set out to solve was specific: when an arrested man claimed a false name, how could the police establish whether he had a prior record? Photographs were in use but not systematic; people changed their appearance; aliases were easy to maintain.

Bertillon's insight was drawn from Adolphe Quetelet's statistical anthropology: adult bone dimensions do not change after about age 20, and the probability of two unrelated adults sharing the same measurements across eleven sites is negligible. If every arrested person was measured at booking, a re-arrest under a false name could be detected by matching the new measurements to the file. The eleven measurements included head length and breadth, the length of the left middle finger, left little finger, left forearm, right ear, and standing height.

Bertillon was allowed a trial from 1882. By 1883 he had his first identification of a recidivist. By 1888 the system was being adopted internationally. He also developed portrait parle (the spoken portrait), a standardised system of describing facial features verbally, so that police in different cities could exchange descriptions of wanted persons in a common language. The portrait parle was the forerunner of modern suspect-description protocols.

Bertillon's fall from dominance came from a combination of two things. First, his system required trained operators, precise equipment, and careful record-keeping; errors accumulated. Second, a case in 1903 exposed its single critical weakness. Will West and William West were two unrelated men in a US federal prison with nearly identical Bertillon measurements. Their fingerprints were entirely different. The case did not disprove anthropometry's logic, but it shattered confidence in the system as a unique identifier and accelerated the adoption of fingerprinting.

Francis Galton (1822-1911) was a Victorian polymath, statistician, and geographer who turned his attention to fingerprints in the late 1880s at the suggestion of his cousin Charles Darwin's champion, Thomas Henry Huxley, and spurred by a paper from Henry Faulds in Nature (1880) suggesting fingerprints could be used in criminal investigation. Galton spent four years collecting, classifying, and counting fingerprint specimens, eventually accumulating over 8,000.

His 1892 book Finger Prints made three foundational contributions. First, it demonstrated permanence: ridge patterns form before birth and do not change across a lifetime. Second, it provided a statistical estimate of uniqueness: even using a simplified count of pattern features, Galton calculated a probability of coincidental match on the order of 1 in 64 billion, far exceeding the world population at the time. Third, it provided a preliminary classification scheme that made filing and retrieval possible, the necessary step between observation and operational use.

Galton was candid about what his system could not yet do: his preliminary classification was incomplete and could not efficiently retrieve a print from a large collection. That operational problem was solved by Edward Henry, who built the Henry classification system from Galton's framework. Galton also collected data that he used to promote eugenic ideas, which sit badly today, but his fingerprint work is separable from those aspects of his career and stands on its own scientific merits. Modern forensic scientists cite the permanence and uniqueness proofs, not the eugenics.

Edmond Locard (1877-1966) trained in both medicine and law at the University of Lyon, where he became an assistant to Alexandre Lacassagne, the leading forensic pathologist in France. He studied under Bertillon in Paris and absorbed the idea that physical evidence, systematically analysed, could identify people and solve crimes. In 1910 the Lyon prefecture gave him two attic rooms and two assistants to establish what became, over the next decade, the world's most influential forensic laboratory.

Locard's exchange principle, stated across his multi-volume writings on criminalistics in the 1920s and 1930s, holds that whenever two surfaces come into contact, material passes between them in both directions. A perpetrator leaves trace material at a scene and carries trace material from it. The principle is a statement about physics, not about detection: it explains why evidence can exist, not that it will always be found or that it will always identify the person. As the previous topic on Locard's principle covers this in depth, the point here is simply its origin in Locard's laboratory practice.

Locard's casework was as important as his theory. He identified a forger by the traces of face powder (lead carbonate and bismuth) found on banknotes the forger had handled. He demonstrated that soil on a suspect's shoes matched the soil composition at the scene of a crime in a case where the suspect denied visiting the location. He showed, in a case involving a strangulation, that scrapings from under the victim's fingernails contained the skin cells of the attacker, matched by anthropometric features to the suspect. Each case put the exchange principle to work and built the evidentiary canon of trace examination.

Leone Lattes (1887-1954) was an Italian medico-legal scientist at the University of Turin. When Karl Landsteiner announced the ABO blood group system in 1901, it was immediately understood that blood groups might be useful forensically. The problem was that Landsteiner's typing method required fresh blood. Dried bloodstains, which are what crime scenes actually produce, lost their reactivity and could not be typed by standard methods.

Lattes's 1915 paper described what became known as the absorption-elution technique. The dried stain is treated with known antibodies (anti-A, anti-B, anti-H). The antigens present in the stain absorb the corresponding antibodies. The stain is washed, then the absorbed antibodies are eluted (released by heating) and their specificity is confirmed by testing them against fresh red blood cells of known groups. The presence or absence of each antigen in the stain is thereby determined even though the stain is dry and the original cells are long broken down.

Lattes wrote the first forensic serology textbook, Individuality of the Blood, in 1932, which established the theoretical framework for using blood-group evidence in criminal and civil cases (including disputed paternity). The limitation he acknowledged, that ABO groups are class characteristics shared by large fractions of the population, did not reduce the technique's usefulness; it shaped how conclusions were expressed. A finding of blood group O on a weapon was never described as proving the victim's blood was present, only as being consistent with it.

Albert Sherman Osborn (1858-1946) was an American document examiner who spent his career trying to turn handwriting analysis from a personal art into a documented scientific discipline. He had watched cases where competing experts gave wildly different opinions on the same document with no way for a court to evaluate whose method was sound. His answer was systematisation.

His 1910 book Questioned Documents covered every aspect of document examination: handwriting analysis, the examination of typewriting and printing, ink chemistry, paper analysis, erasures, alterations, obliterations, and age of documents. His framework required the examiner to specify exactly which features were compared, how many exemplars were used, and what the basis for the opinion was. This was a direct response to the unaccountable expert testimony he had seen in court.

Osborn's most visible case was the Lindbergh kidnapping trial of 1935, in which his handwriting analysis of the ransom notes contributed to the conviction of Bruno Richard Hauptmann. The case was controversial then and remains so, but Osborn's methodology was accepted by the court and became the standard reference for questioned-document examination in the United States through the mid-20th century.

Osborn also co-founded the American Society of Questioned Document Examiners in 1942, establishing the profession's first dedicated learned society. His legacy is thus institutional as well as methodological: he showed that a forensic sub-discipline needed its own professional structure, its own peer community, and its own published standards, not just individual practitioners appearing in court when hired.