Early Forensics in the 1920s: When Science Began to Speak for the Dead
One of the great pleasures—and challenges—of writing historical mysteries is remembering what investigators didn’t know yet. In the 1920s, murder was no longer solved solely by intuition, confession, or a conveniently observant village constable, but neither was it dispatched by gleaming laboratories and instant results. Instead, the decade occupied a fascinating middle ground, where science was just beginning to elbow its way into the mortuary, the police station, and the courtroom.
I was intrigued to include early forensics in my story telling and inspired to create a character like Haley Higgins after watching several episodes of Murdoch Mysteries. Murdoch Mysteries is a long running Canadian program set in Toronto over the period of the late 19th Century into the early 20th century. The character of the pathologist is female with a stomach of steel! She has a dynamic relationship with the lead detective, where they both bring their unique talents together to solve crimes. (The whole supporting characters and the character arcs developing over the series is just great writing. I highly recommend the series. You can watch live streaming of 18 seasons on CBC.)
Here are a few of the early sciences that I've incorporated into Ginger Gold's world.
Fingerprinting
By the early 1920s, fingerprinting had moved from curiosity to cornerstone. Britain had adopted fingerprint identification in 1901 though the execution and delivery of the evidence was long and clunky.
Fingerprints were taken using thick printer’s ink, rolled carefully across each finger and then transferred onto a standardized card. Flat impressions were considered insufficient; officers wanted the full ridge pattern, from nail edge to nail edge. Any slip, smudge, or uneven pressure could ruin a set, which meant suspects were often printed more than once—an uncomfortable, messy business for all involved.
At crime scenes, latent fingerprints were developed using fine powders such as lampblack or aluminum, brushed gently onto surfaces with soft camel-hair or squirrel-fur brushes. It was a delicate art. Too much pressure could erase a print entirely, and poor lighting could mean missing it altogether. Once revealed, prints were photographed or lifted using gummed paper and carefully labeled.
There were no computers waiting to do the work. Fingerprints were classified using the Henry System—loops, whorls, arches—and filed by hand in enormous cabinets. Matching a print meant hours, days, or even weeks of comparison, performed by trained examiners hunched over magnifying glasses.
By the 1920s, courts increasingly trusted fingerprint evidence, and for good reason. It offered something unprecedented: identity that could not be argued away.
Blood Evidence
Blood told a story in the 1920s, but only in broad strokes. Investigators could determine whether a stain was blood and whether it was human, using chemical tests such as guaiac or early phenolphthalein methods. These tests were sensitive enough to detect minute traces, even after attempts at cleaning.
What they could not do was identify whose blood it was. DNA lay decades in the future, and even blood typing was still finding its footing in forensic work. The ABO blood group system could exclude suspects, which was a tremendous aid in policing.
Experienced investigators did pay attention to bloodstains: smears suggested movement, pools implied collapse, and scattered droplets hinted at violence. This was not yet formal bloodstain pattern analysis, but it was a start.
Ballistics
Firearms examination advanced rapidly during the 1920s, driven in part by wartime experience. Investigators were learning that guns left distinctive marks on bullets and cartridge cases, marks that could sometimes be traced back to a specific weapon.
Early ballistics focused on caliber, rifling patterns, and visible striations. Comparison microscopes were beginning to appear, allowing examiners to view two bullets side by side.
The Rise of the Forensic Laboratory and the Mortuary
Perhaps the most significant change of the era was the emergence of dedicated forensic laboratories and specialists. Police forces increasingly relied on pathologists, chemists, and microscopists rather than generalists.
Post-mortem examinations became more systematic. Time of death was estimated using rigor mortis, livor mortis, and body temperature—methods still imprecise, but far more structured than earlier guesswork. Internal injuries were examined with new attention, and causes of death were debated with increasing scientific rigor.
Toxicology also advanced. Poisons such as arsenic, cyanide, and strychnine could be detected through chemical analysis of organs and fluids. Poisoning, once the perfect crime of the genteel murderer, was becoming riskier by the year.
Photography
Crime scene photography became increasingly standardized during the 1920s. Scenes were photographed before disturbance, capturing the position of bodies, furniture, and objects.
Alongside photography came meticulous note-taking, diagrams, and measurements, all recorded by hand. The scene itself was now evidence, not merely the backdrop for a confession.
Why the 1920s Still Matter
What makes early forensics so compelling is not its efficiency, but its humanity. Fingerprint clerks bent over cards. Pathologists chose their words carefully. Investigators learned—often the hard way—that truth did not always align with appearances.
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Cadavers can be deadly...
Unregistered corpses are showing up amongst the cadavers in the mortuary of the London School of Medicine for Women. Unnatural deaths. Murders. The first known victim is recognized by Haley Higgins, a third-year pathology student. War-widow fashionista Ginger Gold feels a responsibility for the man's death and is determined to find his killer.
Her pursuit takes her into the dangerous realm of the famous Italian gangster Charles ''Derby'' Sabini. With the help of Haley and the handsome Chief Inspector Reed - an uneasy alliance - Ginger investigates shady dealings at the docks and at the racehorse stables. What does one have to do with the other, and how are they connected to the bodies piling up at the mortuary? Someone is working on the inside at the school, and Ginger has to find out who before she, or someone she loves, ends up lifeless on a ceramic mortuary slab.
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