Every perpetrator leaves evidence at a crime scene—blood droplets on carpet, fingerprints left as hidden oil patterns on drinking glasses, clothing fibers on corpses. As fans of crime shows know, the forensic team’s job is to find the evidence and unlock its meaning.
But evidence doesn’t have to be tangible. Language also helps solve crimes. Detectives specializing in the growing field of forensic linguistics—word scientists—look for language in ransom notes, threatening texts and other communications that may reveal the offender’s identity or state of mind. They study cadence of speech, grammatical lapses, or terms associated with a specific region. Northerners tend to say faucet, for example, while southerners say spigot. So if a ransom note demands that a bag of money be left by the spigot behind a warehouse, your kidnapper is likely a southerner.
The George Metesky Case
In Michael Cannell’s book Incendiary, about the manhunt for a 1950s serial bomber, detectives noticed a small disparity in dialect that they hoped would lead them to the fugitive’s neighborhood. The bomber made the bombs himself from ordinary pipes and other hardware. In canvassing plumbing outlets, the police found that New Yorkers call a short stretch of galvanized connecting pipe “line pipe coupling.” North of the city the same item was known as “well-coupling.”
The detectives therefore assumed the bomber lived in a northern suburb because he called his pipe “well-coupling.” But they knew little more than that. In desperation, they showed satchels of evidence to Dr. James Brussel, a psychiatrist with a particular interest in the workings of the criminal mind. Dr. Brussel noticed a reliance on awkward, old-fashioned phrases such as “treachery” and “dastardly deeds” in the handful of letters the bomber had sent to newspapers. The letters, he later wrote, “sounded to me as though they’d been written in a foreign language and then translated into English.” So the bomber was probably foreign, but of what nationality?
Detectives suspected the bomber was of German descent because of his vaguely Teutonic handwriting. His G’s ended their circular form with an eccentric pair of horizontal slashes, like an equal sign.
Dr. Brussel concluded the bomber was more likely Slavic after comparing his campaign to the prolific bombings by anarchists and other radicals in Eastern Europe. If the bomber was, in fact, an Eastern European who lived north of the city, he probably lived in Connecticut, where Slavic enclaves had formed around factories and mills. These conclusions, drawn from the bomber’s language and lettering, narrowed the search window.
A few minutes before midnight on January 21, 1957, detectives knocked on the door of a wan, middle-aged man named George Metesky. As Brussel predicted, Metesky was of Lithuanian descent and a resident of the industrial town of Waterbury, Connecticut. While searching Metesky’s house, detectives found a notebook filled with handwriting that appeared to match the bomber’s. They handed Metesky a pen and asked him to write his name on a yellow legal pad. They watched, spellbound, as the familiar block letters appeared on the page—the G in George had the telltale double bars.
The JK Rowling Case
Despite this early success, it took another forty years for forensic linguistics to come into its own. In 1995 The New York Times and Washington Post published the notorious Unabomber’s rambling 35,000-word manifesto. A social worker in Upstate New York named David Kaczynski recognized the idiosyncratic phrasings and alerted authorities. In response, FBI linguist James Fitzgerald matched the language in the manifesto—the Unabomber’s reference to African-Americans as “negros,” for example, and his use of “chimerical” and other rarified words—to letters and other texts written by David Kaczynski’s estranged brother Ted, a math professor turned recluse. Forensic linguistics reached a new level of legitimacy when a judge accepted Fitzgerald’s word analysis as cause to issue a search warrant for Ted Kaczynski’s Montana cabin where police found bomb-making materials.
Today forensic linguistics increasingly relies on computer analysis, as was the case in a recent literary riddle.
Today forensic linguistics increasingly relies on computer analysis, as was the case in a recent literary riddle. “The Cuckoo’s Calling,” a detective novel about a supermodel’s suicide, was published in 2013 to respectable reviews, though critics noted that it was suspiciously polished for a first-time author. The book was written by a retired member of the Royal Military police under the pseudonym Robert Galbraith. Or so it was assumed until The Sunday Times of London received an anonymous tweet claiming that J.K. Rowling was the real author. The mystery novel now had its own mystery.
The Sunday Times hired Patrick Juola, a computer scientist at Duquesne University in Pittsburgh, who used “stylometric” software to compare word usage in “The Cuckoo’s Calling” with the Harry Potter texts. The program considers millions of features, including most frequently used words and patterns of words used together. “Writers can choose to express an idea with a few precise words or bunch of common, general ones,” Juola wrote in Scientific American. “We’re not even conscious of many of these choices.”
Michael Cannell is the author of the new book Incendiary about the manhunt for a 1950s serial bomber. Pick up a copy from Amazon, Barnes & Noble, Indiebound, or Apple.
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