In the early 1930s, we published a series of articles detailing how applied science thwarts criminals. To learn more about the latest in forensics, we visited the Scientific Crime Detection Laboratory in Chicago, where seasoned members of homicide squads learned how to use lie detectors, how to read fingerprints, and how to differentiate different particles of dust beneath a microscope lens. Old methods of methods of nabbing a confession, like confronting a suspect with circumstantial evidence, had been replaced by heartbeat monitors and bloodstain analysis. Forensics breakthroughs occurred in cases like the one where a bank robber filed through a lock, only to be apprehended once authorities determined that the dust on his trouser cuffs matched the metal alloy used in the lock.
Read the full story in "Now -- Real Detectives Beat Sherlock Holmes"