Forensic Experts

In Scotland during the late 1780s, a man was convicted of murder when the soles of his boots matched a plaster cast of footprints taken from the scene of the crime. This is one of the earliest recorded cases of the use of physical evidence to link a suspected criminal with the crime.

In the late 19th century, scientists learned to analyze and classify poisons so their presence could be traced in a body. At about the same time, a controversy arose over the different methods being used to positively identify individuals. Fingerprinting emerged in the early 20th century as the most reliable method of personal identification. With the advent of X-ray technology, experts could rely on dental records to substitute for fingerprint analysis when a corpse was in advanced stages of decomposition and the condition of the skin had deteriorated.

Forensic pathology (medical examination of suspicious or unexplained deaths) also came into prominence at this time, as did ballistics, which is the study of projectiles and how they are shot from firearms. The study of ballistics was aided by the invention of the comparison microscope, which enabled an investigator to look at bullets side by side and compare their individual markings. Since individual gun barrels "scar" bullets in a unique pattern, similar markings found on different bullets may prove that they were fired from the same weapon.

These investigations by pioneer forensic scientists led the courts and the police to acknowledge the value of scientifically examined physical evidence in establishing guilt or innocence, confirming identity, proving authenticity of documents, and establishing cause of death. As the result of this acceptance by the legal and law enforcement communities, crime laboratories were established. One of the first, largest, and most complete laboratories is that of the Federal Bureau of Investigation (FBI), founded in 1932. Today, the FBI laboratory examines approximately one million pieces of evidence each year, and its employees present their findings in trials all over the United States and around the world. As the forensic sciences proved their worth, crime laboratories were established in larger cities and by state police departments. These laboratories are used in turn by many communities too small to support labs of their own. The scientific analysis of evidence has become an accepted part of police procedure, and new forensic techniques, such as those that can detect previously undetectable fingerprints on bullets and knives, are being developed every day.