Modern science and technology have had lasting impacts in the area of criminal investigations. Forensic science enables police, law enforcement, and investigators to detect small amounts of evidence left on items and persons at crime scenes. Certain evidence, such as tiny blood stains, were once invisible to the naked eye and had little value to an investigation because the technology for testing the evidence was simply not invented yet. A criminal always transfers some kind of trace evidence between himself and the victim during every crime. Trace evidence is broad and includes things from soil and paint chips to blood and saliva. It is much more difficult for criminals to get away with crimes today than years past. While the prolific serial killer, John George Haigh, was arrested and tried, forensic science would have made it much easier for law enforcement to identify him as the killer. This paper will provide a general summary of modern forensic science tools and techniques that give law enforcement the ability to accurately identify suspects.
The advent of advanced forensic science techniques has transformed the field of criminal investigations. Investigative feats that were impossible only a few decades ago are now made possible through forensics. Police, law enforcement, and investigators are able to use science to aid in solving crimes that would otherwise go unsolved. Prior to the application of forensic science to investigations, police and other law enforcement personnel were limited in what type of evidence could be recovered and examined from a scene. While certain physical evidence could be retrieved from the scene, such evidence is only as valuable in context. Perhaps the most breakthrough feature that forensic science has enabled is the ability to accurately identify individuals through DNA and fingerprint analysis. Although fingerprint evidence may not be infallible (Cole, 2005, p. 987), the margin of error is infinitesimally small.
Owen provides an overview of two early concepts that were employed to identity potential suspects in criminal cases. In 1876, Cesare Lombroso proposed a foremost means for identifying people. This theory posited the idea all that criminals had unique facial features and other characteristic traits unique to criminal persons (Owen, 2000, p. 18). While this theory introduced the notion that there might be particular ways to identify criminals, there has never been any substantial evidence lending support to a causal link between possessing certain physical characteristics and criminality (Owen, 2000, p. 18). Lombroso’s theory paved the way for other early identification methods. Alphonse Bertillon, in 1879, expanded on the concept of facial measurements as a means to identity individuals (Owen, 2000, p. 21). As technology developed and scientific understanding expanded, more sophisticated techniques for identification were used. Today, fingerprints and DNA evidence serve as reliable sources of identifying one particular person.
John George Haigh
John George Haigh, known as the acid bath murderer, was a disturbing British serial killer. Born in 1909, Haigh grew up in a very strict religious household (Newton, 2006, p. 108). From early on, Haigh displayed obsessions with blood (Newton, 2006, p. 108). Haigh’s first kill occurred din 1944 when he lured an acquaintance, Donald McSwann, into the basement, killed his victim, and later slashed the victim’s throat to drink the blood (Newton, 2006, p. 108). The remains of the body were drowned in an acid vat, where the resultant sludge was discarded into a manhole (Newton, 2006, p. 108). Haigh continued his killing, each time drowning his victims’ remains in acid. Eventually, Haigh was apprehended and put on trial for the murders. In 1949, he was found guilty and sentenced to hanging (Newton, 2006, p. 109).
Computers have enabled crime databases to house records of millions of different fingerprints. Such a large database of fingerprints opens up the potential suspect pool for law enforcement. The speed of which computer programs can search through millions of prints for a match is also a huge asset for law enforcement. The real value of a fingerprint is for comparison purposes. A fingerprint in and of itself is of little use unless it can be matched or compared against a known fingerprint. The large database of fingerprints is particularly valuable when an unknown fingerprint is retrieved from a crime scene and police are looking for a suspect. While Haigh did not leave bodies intact after killing, he did leave his fingerprints on the acid bath and on other incriminating evidence. Forensic scientists would be able to take known fingerprints from Haigh and compare them to the fingerprints found on the acid bath holding the human remains.
One of the most valuable types of evidence that can lead to the apprehension of a suspect is biological evidence. Such evidence includes blood, saliva, and semen. Biological evidence is particularly helpful because it contains DNA. Forensic scientists can examine the biological fluids for DNA and examine the unique DNA profile. Because of the high value of biological evidence, many criminals take care to try and wipe it away before leaving a crime scene. This is most common with blood evidence, where the killer attempts to clean up the bloodstains. Even when blood is not available to the naked eye, however, there are many scientific tests that can detect even the smallest amount of blood (Owen, 2000, p. 190). There are also many chemicals and tests that can be used to differentiate between blood and other substances that may appear like blood (Owen, 2000, p. 190). All persons, with the exception of identical twins, have unique sets of DNA. A small bloodstain can reveal the owner’s DNA profile.
While John George Haigh was arrested and tried for his crimes, many killers have gone free simply because they cannot be caught. There are many murders that remain unsolved. Modern forensic science has made it more likely that crimes and murders will eventually be solved. Evidence that was once invisible to the naked eye are now cracking cold cases wide open. For every crime committed, the criminal leaves some trace of himself behind. The trace might be ever so small, but the smallest piece of evidence could be the largest clue. Whether it is dirt, footprints, blood, saliva, paint chips, or hair, a criminal always leaves something at the crime scene. DNA and forensic science now enables law enforcement to use these tiny pieces of evidence to hunt down the killer. Forensic science is now an essential aspect of criminal investigation and has helped solve many cases.
Cole, S. A. (2005). More than zero: Accounting for error in latent fingerprint identification.
Newton, M. (2006). The encyclopedia of serial killers. New York, NY: Facts On File, Inc.
Owen, D. (2000). Hidden evidence: Forty true crimes and how forensic science helped solve
them. Buffalo, NY: Firefly Books Ltd.