Written in Blood

1. Early Crime Detection Relied on Luck and Persistence, Not Science

For, as incredible as it sounds, at the time Poe wrote ‘Marie Roget’, there was not a police officer in the world who would have thought of trying to solve a crime by the use of scientific logic.

Pre-science era. Before the 19th century, crime detection was rudimentary, often relying on torture to extract confessions, leading to horrific miscarriages of justice like Judge Cambo condemning an innocent man based on flawed legalism rather than his own eyewitness account. The focus was on punishing somebody rather than finding the right person.

Needle-in-the-haystack. Effective detection, when it occurred, was due to sheer persistence and common sense, exemplified by figures like Bow Street Runner Henry Goddard tracking a swindler across America or Paris Sûreté Chief Inspector Louis Canler painstakingly searching hotel registers to find criminals like Lacenaire. These were exceptions, not the rule.

Mistrust of clues. Even when clues were present, like the cravat and bloodstained shirt in the Lady Mazel case, police often failed to apply logic, preferring to rely on confessions, even if obtained under duress. This reflected a societal mistrust of abstract reasoning in legal matters.

2. Poison Was the Perfect Crime Until Chemistry Provided Detection Methods

For more than 2,000 years, poison was the favourite weapon of the assassin.

Ancient and medieval use. From ancient Rome, where figures like Oppianicus and Locusta practiced poisoning as a fine art, through medieval Italy and France (like the Marquise de Brinvilliers and the Affair of the Poisons), poison was favored because it was virtually undetectable by contemporary medicine.

Myths and reality. Legends of poisons that could kill through skin contact or a handshake were common but unfounded. The reality was often the use of substances like arsenic or mercuric chloride, administered in ways that mimicked natural illness, making medical diagnosis difficult or impossible.

Chemistry's dawn. The rise of chemistry in the 18th and 19th centuries began to change this. Scientists like Scheele, Hahnemann, and Metzger developed early tests for arsenic. This culminated in Orfila's systematic toxicology and Marsh's highly sensitive test, making poison detectable and revolutionizing forensic medicine.

3. Chemistry Unlocks Poison's Secrets

My first words were these: toxicology does not yet exist.

Orfila's revelation. Mathieu Joseph Bonaventure Orfila, the "Isaac Newton of toxicology," discovered that common substances like coffee or wine interfered with existing chemical tests for poisons. This led him to realize that the science of detecting poisons in organic matter was virtually non-existent.

Systematic study. Orfila's monumental Treatise on Poisons (1813) systematically detailed how to detect various poisons even when mixed with food or bodily fluids. His work transformed toxicology into a rigorous science, providing doctors with the knowledge needed to identify poisons during autopsies.

Marsh test impact. James Marsh's invention of a highly sensitive test for arsenic in 1836 further advanced the field, allowing detection of minute quantities. Orfila's application of the Marsh test in cases like Marie Lafarge's poisoning trial solidified the role of scientific evidence in court, despite initial jury skepticism.

4. Fingerprints Revolutionized Criminal Identification, Overcoming Earlier Systems

For, as incredible as this sounds, at the time Poe wrote ‘Marie Roget’, there was not a police officer in the world who would have thought of trying to solve a crime by the use of scientific logic.

Beyond anthropometry. While Alphonse Bertillon's anthropometry (measuring body parts) was a significant step beyond simple photographs for criminal identification, it was complex and prone to error. The true revolution came with the recognition that fingerprints are unique and permanent.

Pioneering work. Figures like William Herschel, Henry Faulds, and Sir Francis Galton laid the groundwork, recognizing the uniqueness of fingerprints. However, the challenge was classification.

Classification breakthroughs. Juan Vucetich in Argentina developed a practical classification system, solving the first fingerprint murder in 1892 (Francisca Rojas case). Edward Henry in India created a more robust system adopted by Scotland Yard in 1901, proving far more efficient than bertillonage and leading to convictions like the Stratton brothers.

5. The Microscope Unlocked a Hidden World of Trace Evidence

Edmond Locard had formulated the basic principle of scientific crime detection: ‘Every contact leaves a trace.’

Early observations. Even before forensic science, individuals like Antonie Van Leeuwenhoek used early microscopes to study tiny details like hair structure. However, its application to crime was sporadic.

Pioneering cases. The Praslin Affair (1847) saw the microscope used to identify skin fragments and hair on a murder weapon. Later, figures like Professor R. A. Riess used microscopic analysis of hairs and dust to deduce characteristics of criminals, as seen in the Marie Pallot case.

Locard's principle. Edmond Locard, the "French Sherlock Holmes," established the fundamental principle that a criminal always leaves something behind and takes something away. His laboratory work, analyzing dust, fibers, and other microscopic traces, proved invaluable in solving cases like the coiners and the railway postman, solidifying the microscope's role as a detective tool.

6. Ballistics Transformed Bullet Marks into Unique Signatures

Balthazard argued, means that every bullet that has been fired has its own individuality—in fact, its own fingerprint.

Early attempts. Initial ballistic analysis was crude, sometimes relying on paper wads found in wounds (Culshaw, Richardson). Henry Goddard's identification of a bullet from a specific mold in 1835 was an early exception, but systematic study was lacking.

Grooves and striations. The invention of rifling (spiral grooves in barrels) to improve accuracy created unique marks on bullets. Lacassagne in France first used these groove patterns to link a bullet to a suspect's gun in 1889.

Comparison microscope. The invention of the comparison microscope by Philip Gravelle in 1923, championed by Charles Waite and Calvin Goddard, allowed direct side-by-side comparison of microscopic striations on bullets and cartridge cases, establishing ballistics as a precise science capable of linking a bullet to a specific firearm, famously used in the St Valentine's Day Massacre investigation.

7. Identifying the Dead Became a Science of Reconstruction and Detail

To write the history of identification is to write the history of criminology.

Beyond recognition. Identifying unknown bodies, especially when mutilated or decomposed, was historically difficult, relying on unreliable eyewitness accounts or limited physical traits (Catherine Hayes, William Sheward). The Campden Wonder remains a cautionary tale about convicting without a body.

Systematic pathology. Professor Alexandre Lacassagne pioneered systematic methods, using skeletal analysis to deduce characteristics like gait (Gouffé case). Later pathologists like Sir Bernard Spilsbury (Crippen, Mahon) and Professor John Glaister (Ruxton) became masters of reconstructing bodies and determining cause of death from remains.

Modern techniques. Advances in anthropology, odontology (dental records), and eventually DNA analysis, combined with meticulous scene investigation and reconstruction (Keith Simpson, Mike Sayce), have made identification possible even from fragmented remains or in 'no-body' cases (Rose Michaelis, Alison Day).

8. The Rise of Sex Crime Presented a New, Baffling Challenge

As strange as it sounds, sex crime is a relatively modern phenomenon.

Historical context. While rape has always existed, obsessive, random sex crime was rare before the 19th century. Factors like widespread poverty, lack of privacy, and different social structures meant sexual outlets and motivations differed significantly from later periods.

Victorian influence. Victorian prudery and the rise of pornography fueled sexual fantasy and obsession, creating a disconnect between imagination and reality. This, combined with increasing social stratification limiting access to women, contributed to the emergence of sex crimes driven by compulsion rather than opportunity.

Early cases and the Ripper. Early sex murderers like Frederick Baker or Eusebius Pieydagnelle were often seen as cases of 'moral insanity'. The Jack the Ripper murders (1888) were the first to shock the world with their seemingly random, savage nature, highlighting the terrifying challenge posed by the unknown, compulsive sex killer to existing detection methods.

9. Random Killers Tested the Limits of Traditional Detection

To criminologists of the future, the year 1960 may seem a watershed in the history of crime.

Post-WWI surge. The violence of World War I seemed to unleash a new era of sex crime in Europe, marked by figures like Bela Kiss, Peter Kürten, and Fritz Haarmann, whose motives often seemed rooted in sadistic compulsion rather than simple gain.

Elusiveness. These random killers, like Joseph Vacher or Earle Nelson, proved incredibly difficult to catch using traditional methods, as they lacked a clear link to their victims and operated unpredictably across wide areas, exposing the limitations of detection reliant on motive and known associates.

Psychological dimension. Cases like Leopold and Loeb highlighted that crime could be driven by complex psychological factors like boredom, fantasy, and a desire for excitement, rather than just economic need or simple passion, foreshadowing the need for new approaches to understanding the criminal mind.

10. Psychological Profiling Added a New Dimension to Understanding Criminals

His final picture of the bomber was of a man in his 50s, Slavic in origin, neat and precise in his habits, who lived in some better part of New York with an elderly mother or female relative.

Beyond motive. Recognizing that some crimes, particularly serial offenses, lacked clear rational motives, police began seeking psychological insights. Dr James Brussel's accurate profile of the "Mad Bomber" George Metesky demonstrated the potential of deducing personality traits from criminal behavior.

FBI's Behavioral Science Unit. Building on early efforts, the FBI established a unit to systematically study serial offenders, interviewing convicted murderers to build profiles based on shared characteristics and behaviors. This provided investigators with tools to narrow suspect lists and guide interrogations.

Understanding the criminal mind. Research by figures like Yochelson and Samenow explored the core traits of the criminal personality, highlighting self-centeredness, immaturity, and self-delusion. Dan MacDougald's work on "faulty blocking mechanisms" suggested that criminals selectively ignore reality, offering a new perspective on their motivations and potential for change.

11. Modern Forensics Leverages Computers and DNA for Unprecedented Identification

Alec Jeffreys, of the University of Leicester, made the discovery superfluous when he stumbled upon a completely new method of ‘typing’ an individual: the DNA fingerprint.

Technological advancements. Post-WWII forensics saw significant progress in areas like spectroscopy for analyzing trace evidence (paint, fibers) and improved serological tests (Ouchterlony, Kind's absorption elution). These techniques provided increasingly precise links between suspects and crime scenes.

Computer power. The advent of computers revolutionized data management, making it possible to store and rapidly search vast databases of fingerprints and other criminal records, dramatically increasing the efficiency of identification.

DNA fingerprinting. The discovery of DNA fingerprinting by Alec Jeffreys in 1984 provided the ultimate identification tool, capable of linking a suspect to biological evidence (blood, semen, hair) with unprecedented certainty, even in cases lacking traditional clues or a body, transforming the landscape of criminal investigation.

12. Persistence and Collaboration Remain Essential in the Manhunt

It should also be clear that the Ripper was caught by police work as much as by chance.

Beyond the lab. While scientific advancements provide powerful tools, the craft of the manhunter still relies heavily on traditional police work: painstaking interviews, following leads, cultivating informants, and maintaining surveillance.

Collaboration is key. Complex cases increasingly require the collaboration of multiple forensic disciplines (pathology, serology, ballistics, microscopy, anthropology, entomology) and seamless communication between laboratory scientists and field detectives, as seen in cases like the Backhouse bombing or the Karen Price identification.

The human element. Despite technology, intuition, persistence, and the ability to read human behavior remain vital. Cases like the Mad Bomber, the Railway Rapist, or the Ronald Harries double murder demonstrate that a detective's hunch, a witness's memory, or a suspect's slip-up can still be the crucial factor that breaks a case.

Last updated: July 8, 2025