Connecting the Dots: The Science of CSI

Connecting the Dots

The Science of CSI

Photography

Six criminals published in Thomas Byrnes’ Professional Criminals of America. Note the diverted or closed eyes in the top row. The photograph of Edward Lyons, bottom left, was taken while the suspect was asleep in a hospital bed. Image source: Byrnes, Thomas. 1886 Professional Criminals of America. 1886. Chelsea House, 1969.

Rogues’ Galleries

In the decades following the invention of photography in the 1830s, police departments began using photographs as a means to identify criminals. Law enforcement agencies in large cities created files of thousands of portraits that became known as “rogues’ galleries.” The photographic collections lacked standardization and suspects would often try to disguise their faces. The objectivity of photographs was never questioned by the police. “The very cleverest hands at preparing a false physiognomy for the camera have made their grimaces in vain,” noted New York City police detective Thomas Brynes in his 1886 book on criminals. The value of a rogues’ gallery is in the details, he argued. A skilled detective looks for a distinguishing mark of a suspect. “It did not matter much what disguise he assumed. That feature would remain a tell-tale.”


Suspects were reluctant to have their pictures taken and had to be forced to sit for a portrait. Thomas Byrnes, far left, watches as his men wrestle a suspect into position to be photographed. Image source: Byrnes, Thomas. 1886 Professional Criminals of America. 1886. Chelsea House, 1969.

Image source: Galton, Francis. Proceedings of the Royal Institution of Great Britain, vol. IX, no. See Source

Composite Photography

In 1879, Francis Galton introduced composite photography in an attempt to identify common physical characteristics of criminals. In this image, Galton showed composites of criminals who had been convicted of violent crimes. Galton noted two common features among this criminal population. One is an overall frame that is “broad and massive, like those of Henry VIII, but with a much smaller brain.” The other feature is a face that is “weak and certainly not a common English face.” Despite this early claim, Galton eventually found that any peculiar feature of a criminal became “normal” in composites and that there is no link between physical features and the criminal mind. In the 1880s, Galton founded the eugenics movement and continued his composite photography work in ethnological studies.


Image source: Frazer, Persifor. “Identification of Human Beings by the System of Alphonse Bertillon.” The Journal of the Franklin Institute, vol. 167, no. 9, 1909. View Source

Bertillonage

In 1879, Alphonse Bertillon, a police officer in Paris, France, introduced an identification system that combined detailed physical measurements of suspects and their photographs. Bertillon photographed each suspect twice: once full face and once in profile, and added the photographs to an identification card that listed body measurements. The identification system, which became known as Bertillonage, was adopted by law enforcement agencies throughout the world. Fingerprinting displaced Bertillonage by the 1920s, but Bertillon’s standardized process of photographing suspects became the forerunner of the familiar-looking mug shot of today.


Francis Galton’s portrait on a Bertillon card he received while visiting Bertillon’s Paris laboratory in 1893. Image source: Pearson, Karl. The Life, Letters and Labours of Francis Galton, vol. 1. Cambridge University Press, 1930. View Source


Bertillon devoted great effort to photograph, describe, and classify body parts—eyes, ears, noses, mouths, hair, and even facial wrinkles. Police officers would then use these descriptive terms to complete Bertillonage cards for a suspect.

Image source: Frazer, Persifor. “Identification of Human Beings by the System of Alphonse Bertillon.” The Journal of the Franklin Institute, vol. 167, no. 9, 1909.

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