How Forensic Lab Techniques Work

History of Forensics


Investigating a hat.
Kurt Hutton/Picture Post/Getty Images
A scientist at Preston Forensic Science Laboratory removes a hair from a hat left at the scene of a shooting in the 1940s.

The history of forensic science dates back thousands of years. Fingerprinting was one of its first applications. The ancient Chinese used fingerprints to identify business documents. In 1892, a eugenicist (an adherent of the often prejudiced system of scientific classification) named Sir Francis Galton established the first system for classifying fingerprints. Sir Edward Henry, commissioner of the Metropolitan Police of London, developed his own system in 1896 based on the direction, flow, pattern and other characteristics in fingerprints. The Henry Classification System became the standard for criminal fingerprinting techniques worldwide.

In 1835, Scotland Yard's Henry Goddard became the first person to use physical analysis to connect a bullet to the murder weapon. Bullet examination became more precise in the 1920s, when American physician Calvin Goddard created the comparison microscope to help determine which bullets came from which shell casings. And in the 1970s, a team of scientists at the Aerospace Corporation in California developed a method for detecting gunshot residue using scanning electron microscopes.

Forensic Lab Safety
The job of a forensic scientist involves using a variety of chemicals, which can be flammable, corrosive and even explosive if not handled properly. Here are a few tips that forensic labs follow to ensure that their employees stay safe:
  • Labs should have procedures in place for the use and disposal of chemicals, as well as a safety plan in case of emergency (including a safety shower and eyewash station).
  • Employees need to be well-trained in the use of all chemicals, understanding the properties of each chemical and its potential to cause injury.
  • Lab technicians should wear the proper gear -- eyewear to protect against chemical splashes and gloves to protect their hands.
  • Chemical containers should be properly labeled with the correct chemical name.
  • Flammable liquids should always be kept in special storage containers or a storage room. Putting these types of chemicals in a regular refrigerator can lead to an explosion.

In 1836, a Scottish chemist named James Marsh developed a chemical test to detect arsenic, which was used during a murder trial. Nearly a century later, in 1930, scientist Karl Landsteiner won the Nobel Prize for classifying human blood into its various groups. His work paved the way for the future use of blood in criminal investigations. Other tests were developed in the mid-1900s to analyze saliva, semen and other body fluids as well as to make blood tests more precise.

With all of the new forensics techniques emerging in the early 20th century, law enforcement discovered that it needed a specialized team to analyze evidence found at crime scenes. To that end, Edmond Locard, a professor at the University of Lyons, set up the first police crime laboratory in France in 1910. For his pioneering work in forensic criminology, Locard became known as "the Sherlock Holmes of France."

August Vollmer, chief of the Los Angeles Police, established the first American police crime laboratory in 1924. When the Federal Bureau of Investigation (FBI) was first founded in 1908, it didn't have its own forensic crime laboratory -- that wasn't set up until 1932.

By the close of the 20th century, forensic scientists had a wealth of high-tech tools at their disposal for analyzing evidence from polymerase chain reaction (PCR) for DNA analysis, to digital fingerprinting techniques with computer search capabilities.

Next, we'll see some of the applications of these modern forensic technologies.