The first United States police force began the use of fingerprints in suspect identification in October 1904. But how fingerprints came into law enforcement took a world's fair and a case of mistaken identity.
Dating back to the beginning of the 20th century, the most common way to identify criminal suspects was through The Bertillon System.
This method of investigation was named after its creator anthropologist, Alphonse Bertillon. His system measured the dimensions of the body to identify people. It was through these measurements that you could differentiate between similar-looking people.
It was widely used by United States prison system to catalog prisoners. The system worked for about 30 years.
Then, in 1903 something strange happened.
A man named William West was sentenced to prison in Leavenworth, Kansas. When he got to the prison, officials were confused. They already had a file for a William West who had been arrested for murder and looked the same.
When the newly arrived William West protested that he had never been convicted of murder, officials ignored him.
However, when they looked in the prison, the realized there was in fact already a William West still there serving a murder conviction.
The two men had the same face, Bertillon measurements and name. So, how do you separate the two?
Around that same time, famed Scotland Yard had perfected a system of fingerprinting suspects. This uniqueness of fingerprints was really nothing new. At different points in history, cultures have used fingerprints to show differences in people. But Scotland Yard’s detectives were the first to create a system with it to identify suspects.
Sure, enough prison officials found the two William Wests had different prints and solved the issue
A year later at the St. Louis World’s Fair, Scotland Yard showed off their finger print system. Between the display and the William Wests case, St. Louis police were sold.
October 1904 marks when St. Louis detectives became the first police in the United States to keep a finger print database.