# Forensic science: from fingerprints to junk science

How the science of evidence rose and where it failed: Bertillon and fingerprints, Locard's exchange principle and the first crime labs, ballistics and DNA profiling, set against the discredited bite-mark and hair analysis, the arson myths behind the Willingham execution, and the DNA-driven exonerations.

*This story parallel: The history of policing and the police state*
*This story parallel: Colonization: the making of the modern world*
*This story parallel: The loyalists won: who inherited Kenya's independence*
*This story part of: Science and technology*
*Science and technology parallel this story*

## 1858 — Fingerprinting is born as a tool of colonial control

Fingerprinting entered official use not as forensics but as a technology of colonial control. William Herschel, a British administrator in Bengal, began taking handprints and fingerprints from 1858 to bind Indians to contracts and pensions and to tell colonial subjects apart. Edward Henry later systematized the method in India before carrying the Henry Classification to Scotland Yard. The same logic reached Kenya in the Native Registration Ordinance, whose kipande fingerprinted every African man for labour control.

## 1883 — Bertillon anthropometric identification system adopted by Paris police

Alphonse Bertillon's system of measuring body dimensions to identify repeat offenders was formally adopted by the Paris police prefecture. It was the first systematic method used by a police force to identify individuals, and it spread to other countries over the following two decades. Bertillonage was later displaced by fingerprinting, which proved more reliable and easier to apply.

## c. 1891 — Juan Vucetich creates the first fingerprint classification system

Working for the police in Buenos Aires province, Croatian-Argentine police official Juan Vucetich developed a practical system for classifying and filing fingerprints for criminal identification. His system predated and ran parallel to the Galton-Henry system used in Britain. Argentina became the first country to make fingerprinting its official method of criminal identification.

## 1892 — Francis Galton publishes Finger Prints

Francis Galton published Finger Prints, the first book to establish that fingerprint patterns are unique to individuals and persist unchanged through life. The book provided the statistical and classification groundwork that police forces would later use to build fingerprint identification systems. Galton's classification scheme was later refined by Edward Henry into the system Scotland Yard adopted.

## c. June 1892 — First fingerprint-based criminal conviction, the Rojas case

Francisca Rojas was convicted of murdering her two children after a bloody fingerprint left at the scene matched hers, using Juan Vucetich's newly developed classification system. It is documented as the first criminal case solved using fingerprint evidence. The case demonstrated fingerprinting's evidentiary value years before it was widely adopted elsewhere.

## 1893 — Hans Gross publishes Criminal Investigation and coins criminalistics

Austrian magistrate Hans Gross published Handbuch fur Untersuchungsrichter, translated as Criminal Investigation, laying out methods for applying science to police work. He coined the term criminalistics for this approach. The book became a foundational text for early crime laboratories across Europe.

## 1901 — Karl Landsteiner discovers human blood groups

Karl Landsteiner identified the A, B, and O blood groups, work for which he later won the Nobel Prize. The discovery gave forensic investigators a way to distinguish blood samples and, eventually, to include or exclude suspects based on blood type found at crime scenes. Blood typing remained a core forensic serology tool until DNA profiling replaced it.

## 1901 — Scotland Yard adopts the Henry Classification fingerprint system

Edward Henry, building on Galton's research, developed a fingerprint classification system practical for large-scale police filing. Scotland Yard adopted the Henry system, establishing a Fingerprint Branch and phasing out Bertillon's anthropometric measurements. The system, with later modifications, became the basis for fingerprint filing used by police forces around the world for most of the twentieth century.

## c. September 1902 — First fingerprint conviction in Britain, the Harry Jackson case

Harry Jackson was convicted of burglary after a fingerprint left on a freshly painted windowsill matched his prints on file with Scotland Yard's new Fingerprint Branch. It was the first criminal conviction in Britain secured using fingerprint evidence. The case helped establish fingerprinting as credible courtroom evidence in the British legal system.

## 1910 — Edmond Locard founds the first forensic crime laboratory

Edmond Locard established a police laboratory in Lyon dedicated to the scientific examination of physical evidence, generally regarded as the first crime laboratory of its kind. Locard is best known for articulating the exchange principle, the idea that every contact between a criminal and a crime scene leaves a trace. His laboratory became a model that other countries, including the FBI, later copied.

## c. 1915 — Leone Lattes develops a forensic test for dried blood stains

Italian physician Leone Lattes developed a method for determining the ABO blood group of dried bloodstains, applying Landsteiner's discovery directly to crime scene evidence. This gave investigators a practical way to test blood found at scenes rather than only fresh samples. The technique was used in criminal cases across Europe in the following decades.

## 1918 — Office of Chief Medical Examiner founded in New York City

New York City replaced its politically appointed coroner system with the first medical examiner's office in the United States, led by pathologist Charles Norris. Norris hired chemist Alexander Gettler, who built the office's toxicology laboratory and is widely regarded as the father of American forensic toxicology. Together they developed methods for detecting poisons that other jurisdictions later adopted.

## 1921 — John Larson invents the modern polygraph

Police officer and physiologist John Larson built the first modern polygraph, a device recording blood pressure, pulse, and respiration to detect deception. The device was adopted by police departments despite the lack of scientific consensus that its readings reliably indicate lying. Courts have generally excluded polygraph results as evidence, and no major scientific body has validated it as an accurate lie-detection method.

## 1923 — Frye v. United States sets the general acceptance standard for scientific evidence

A federal appeals court ruled that a precursor to the polygraph, a systolic blood pressure deception test, could not be admitted as evidence because the underlying technique had not gained general acceptance in the relevant scientific community. The resulting Frye standard governed the admissibility of scientific evidence, including many forensic disciplines, in most U.S. courts for the next seventy years. It was eventually superseded in federal courts by the Daubert standard.

## 1 July 1924 — FBI establishes a centralized fingerprint Identification Division

The FBI, under J. Edgar Hoover, created an Identification Division to consolidate fingerprint records from police departments nationwide into a single federal repository. The division absorbed existing collections and grew into the largest fingerprint archive in the world. It gave American law enforcement a national system for identifying repeat offenders across jurisdictions.

## c. 1927 — Calvin Goddard's comparison microscope used in the Sacco and Vanzetti case

Firearms examiner Calvin Goddard used a comparison microscope, which lets an examiner view two bullets side by side, to re-examine ballistics evidence in the contested murder case against Nicola Sacco and Bartolomeo Vanzetti. The technique demonstrated that microscopic markings on bullets could be matched to a specific firearm. The case helped establish the comparison microscope as a standard tool of firearms identification.

## c. 1929 — Calvin Goddard's ballistics analysis identifies the St. Valentine's Day Massacre weapons

Following the February 1929 machine-gun killing of seven men in a Chicago garage, Calvin Goddard used firearms comparison to match spent shell casings to specific Thompson submachine guns later recovered from a suspect in Michigan. The analysis was widely publicized and demonstrated firearms identification as courtroom-credible science. Goddard went on to found the Scientific Crime Detection Laboratory at Northwestern University, one of the first university-based crime labs in the United States.

## 24 November 1932 — FBI Laboratory is founded

The FBI opened its Technical Laboratory, offering forensic analysis of physical evidence, including firearms, documents, and chemical traces, to police departments across the country free of charge. It grew into the largest and most influential crime laboratory in the United States. Decades later some of its units, particularly hair microscopy and bullet-lead analysis, would become central to the reckoning over unvalidated forensic methods.

## c. 1945 — Frances Glessner Lee creates the Nutshell Studies of Unexplained Death

Frances Glessner Lee, a wealthy heiress often called the mother of forensic science, built a series of detailed miniature crime scene dioramas, the Nutshell Studies of Unexplained Death, to train police investigators in careful observation of physical evidence. She used them in seminars for Harvard's department of legal medicine, one of the first formal forensic training programs for police in the United States. The dioramas are still used in forensic training today.

## 1962 — Lawrence Kersta introduces voiceprint identification

Bell Labs engineer Lawrence Kersta proposed that spectrographic analysis of a person's voice, which he called a voiceprint, could reliably identify individual speakers, drawing an analogy to fingerprints. Some police departments and courts began admitting voiceprint testimony, but later scientific review found the method lacked adequate validation and a demonstrated error rate. Courts became increasingly reluctant to admit voiceprint evidence as its scientific basis was questioned.

## c. July 1979 — Bite-mark evidence helps convict Ted Bundy

In the trial for the Chi Omega sorority house murders, prosecutors used bite-mark comparison testimony to help convict Ted Bundy, a case widely credited with popularizing forensic odontology in American courts. Bite-mark analysis, which compares injury patterns on skin to a suspect's teeth, spread to other prosecutions over the following decades. It would later be shown to lack scientific validation and to have contributed to numerous wrongful convictions.

## c. 10 September 1984 — Alec Jeffreys develops DNA fingerprinting

Geneticist Alec Jeffreys discovered that certain repeating DNA sequences vary enough between individuals to serve as a unique identifier, a technique he called DNA fingerprinting. The discovery, made at the University of Leicester, gave forensic science its first method for identifying individuals from biological evidence with very high statistical confidence. Within two years it was applied to a criminal investigation for the first time.

## c. November 1986 — DNA testing exonerates Richard Buckland in the Enderby murders

Richard Buckland had confessed to the murder of Dawn Ashworth, but Alec Jeffreys's new DNA profiling technique showed his DNA did not match semen recovered from the crime scene, and also linked the same, unknown perpetrator to an earlier unsolved murder. Buckland was released, making him the first person cleared of a crime through DNA evidence. Police then organized a mass DNA screening of local men to find the actual killer.

## 22 January 1988 — Colin Pitchfork becomes the first person convicted using DNA evidence

Colin Pitchfork was identified through the mass DNA screening prompted by the Enderby murders investigation, after he arranged for a friend to submit a sample in his place, and pleaded guilty to the rapes and murders of two teenage girls. It was the first criminal conviction in the world secured using DNA profiling. The case demonstrated both the power of DNA evidence and its ability to clear the innocent alongside catching the guilty.

## 1992 — Innocence Project founded

Attorneys Barry Scheck and Peter Neufeld founded the Innocence Project at Cardozo School of Law to use DNA testing to reinvestigate convictions where biological evidence remained available. The organization has since helped exonerate hundreds of wrongfully convicted people in the United States, many of whose convictions relied on forensic testimony later shown to be flawed. Its casework became a major driver of scrutiny into unvalidated forensic disciplines.

## 1993 — Daubert v. Merrell Dow Pharmaceuticals reshapes the standard for scientific evidence

The U.S. Supreme Court ruled that federal judges, not just professional consensus, must act as gatekeepers for scientific evidence, weighing factors such as testability, error rates, and peer review rather than relying solely on general acceptance. The Daubert standard replaced the 1923 Frye standard in federal courts and many states. It gave judges a clearer tool to exclude forensic testimony that had not been scientifically validated, though many courts continued to admit contested disciplines for years afterward.

## c. June 1993 — Kirk Bloodsworth becomes the first death-row inmate exonerated by DNA

Kirk Bloodsworth had been sentenced to death for the rape and murder of a child based largely on eyewitness identification and bite-mark testimony. DNA testing of crime scene evidence proved he was not the perpetrator, and he was released after roughly nine years in prison, becoming the first American death-row inmate exonerated by DNA evidence. The actual perpetrator was later identified through a DNA database match.

## 17 February 2004 — Cameron Todd Willingham executed after flawed arson forensics

Cameron Todd Willingham was executed for setting a fire that killed his three children, a conviction built on arson investigators' testimony that has since been discredited by fire science experts. Independent reviews commissioned after his execution, including by the Texas Forensic Science Commission, concluded the original investigators relied on outdated folk beliefs about fire behavior rather than validated science. The case became a central example cited in later reports on unreliable forensic testimony.

## c. February 2004 — National Academy of Sciences finds bullet-lead analysis unreliable

A National Academy of Sciences report, Forensic Analysis: Weighing Bullet Lead Evidence, reviewed the FBI's technique of matching bullets by trace chemical composition and concluded the underlying assumptions were not scientifically supported. The technique, used in thousands of cases since the 1960s, had claimed to trace bullets to a specific manufacturing batch. The report's findings directly contradicted decades of FBI expert testimony presented to juries as reliable science.

## c. May 2004 — Brandon Mayfield wrongly linked to the Madrid train bombings by an FBI fingerprint error

The FBI arrested Oregon attorney Brandon Mayfield and held him as a material witness after its examiners misidentified a partial fingerprint from the March 2004 Madrid train bombings as his. Spanish authorities disputed the match, and the fingerprint was later confirmed to belong to an Algerian national with no connection to Mayfield. The FBI publicly apologized, paid a settlement, and an internal review documented flaws in fingerprint examiners' methodology and bias, prompting reforms to latent fingerprint procedures.

## 1 September 2005 — FBI discontinues comparative bullet-lead analysis

Following the National Academy of Sciences' 2004 critique, the FBI announced it would stop performing comparative bullet-lead analysis, the technique used since the 1960s to try to match bullets to a common manufacturing source. The bureau acknowledged the method's scientific basis did not support the strength of the conclusions examiners had presented in court for decades. The decision prompted new legal appeals in cases where the discredited analysis had contributed to convictions.

## 18 February 2009 — National Academy of Sciences report Strengthening Forensic Science is published

The National Academy of Sciences released Strengthening Forensic Science in the United States: A Path Forward, a congressionally mandated review concluding that, apart from nuclear DNA analysis, no forensic discipline had been shown through rigorous scientific study to reliably and consistently connect evidence to a specific individual or source. The report criticized fields including bite-mark analysis, hair and fiber comparison, and firearms identification for lacking established error rates and standardized protocols. It called for an independent federal agency to oversee and fund forensic science research, a recommendation that was never fully implemented.

## c. December 2012 — Santae Tribble exonerated after hair evidence proven wrong

Santae Tribble had served nearly 28 years in prison for a murder conviction based partly on an FBI examiner's testimony that a hair found at the scene matched his. DNA testing later showed the hair did not even belong to a human, but to a dog, and Tribble was exonerated. The case became one of several that exposed the unreliability of microscopic hair comparison as practiced by FBI examiners for decades.

## 18 April 2015 — FBI and Justice Department admit flawed hair microscopy testimony in most cases reviewed

The FBI and the Department of Justice, in a joint review with the Innocence Project and the National Association of Criminal Defense Lawyers, acknowledged that FBI hair examiners had given scientifically invalid testimony overstating the certainty of microscopic hair comparison in at least 90 percent of the roughly 250 trial transcripts reviewed at that point. The flawed testimony was found in cases spanning decades, including some that ended in death sentences. The admission was described as one of the largest forensic scandals in United States history and prompted a wider review of thousands of additional cases.

## 8 April 2016 — Keith Harward exonerated after bite-mark evidence proven false

Keith Harward had spent 33 years in prison for a rape and murder conviction based on testimony from multiple forensic dentists that his teeth matched bite marks left on the victim. DNA testing identified another man as the actual perpetrator, and Harward was exonerated and released. His case, one of the longest-serving bite-mark exonerations, was cited by the American Board of Forensic Odontology and legal reform advocates as evidence the technique lacked scientific reliability.

## c. April 2016 — Texas Forensic Science Commission rejects bite-mark analysis as scientifically invalid

The Texas Forensic Science Commission recommended a moratorium on the use of bite-mark comparison evidence in criminal cases, concluding the method lacked scientific foundation. Texas became the first state to formally move to bar the technique from courtrooms. Several wrongful convictions built on bite-mark testimony, including cases in Texas, had already been overturned by that point.

## 20 September 2016 — PCAST report on forensic feature-comparison methods is published

The President's Council of Advisors on Science and Technology released Forensic Science in Criminal Courts: Ensuring Scientific Validity of Feature-Comparison Methods, reviewing disciplines including bite-mark analysis, firearms identification, footwear analysis, and latent fingerprint examination. The report found that bite-mark analysis had not been shown to be reliable and should not be treated as a valid method, and that several other pattern-matching disciplines lacked adequate studies establishing their accuracy and error rates. It reinforced and extended the 2009 National Academy of Sciences findings, adding pressure for courts and crime labs to reconsider what forensic testimony should be admitted.