Ray Harrington was the well-regarded Head of the Minneapolis Police Bureau of Identification during the 1930s.
He was responsible for establish the Minneapolis Police Detection Training School to train Detectives in the various methods of gathering evidence. In his opinion, Detectives needed to understand something of physics, chemistry, geology, pathology, handwriting, and fingerprint classification. They also needed to be able to establish a rapport with people.
In the training sessions of April of 1938, Mr. Harrington met with Detectives three days per week to teach them about the tools and machinery of the Bureau of Identification. He instructed them in the fingerprint system and taught them how to obtain, determine the value of, and eliminate fingerprints.
He also taught them about something called the “portrait parle” or the “talking picture.” This was the term for the process of obtaining a complete description of a perpetrator from a victim.
Detectives were also trained in gathering blood, soil and metal samples.
The mission of the Detection Training School was to place the full power of Science into the hands of the Detectives with the goal of helping them solve crimes more quickly and with greater ease.
Photograph courtesy of Hennepin County Library