The science of policing

Not too long ago, new police recruits were told when to show up for work and assigned to a beat, often with little more than a few hours training. Most had to buy their own weapons and if evidence was collected at all, it was as an afterthought and with little accountability.

But as science progressed, so did policing. Evidence collection, processing and analysis grew more focused and exacting. Researchers delved into the mysterious workings of the mind, found ground-breaking new ways to identify criminals and victims and made the streets safer for the officers who patrolled them.

Join us below as LET celebrates a few of the many scientists whose works have contributed to the success of modern policing.

An accidental discovery continues to save lives

Chemist Stephanie Kwolek's curiosity and a willingness to see things through became a lifesaver for thousands of police officers, service members and firefighters the world over.

The young DuPont chemist had been experimenting in her research laboratory, searching for a new method in which to manufacture fibers and polymers (large molecules, which occur either synthetically or naturally, that are comprised of simple repetitive units). She and other researchers had been asked to find high-performance fibers that could reinforce rubber tires and make them more durable.

Kwolek's experiments led her to discover an odd opalescent substance that, she has said, most chemists would have discarded, but she thought there might be something to this new chemical compound she'd found. Kwolek asked that it be tested by another part of the lab, which specialized in spinning the liquids to measure, among other things, their strength and stiffness. Although rebuffed several times, Kwolek persisted until they spun the substance and the numbers were surprising. Kwolek retested the substance several times before taking her find to her bosses. Her discovery launched a new field of study in polymer chemistry.

The consumers that DuPont initially targeted—tire companies—weren't terribly interested in the new substance because using it meant they'd have to retrofit their production lines. However in 1971 DuPont introduced its find as Kevlar. Today, Kevlar has dozens of applications: It is used in bicycle tires and other sporting equipment, in musical instruments such as the reeds on woodwinds and as drumheads, to construct ropes, brakes, hoses, and even as a substitute for Teflon in some frying pans.

But its most significant application turned out to be as a component of protective gear for emergency responders. In addition to vests and gloves for police, Kevlar is also employed in turnout gear for firefighters and became widely used by the U.S. Armed Forces to make facemasks, helmets and armored vehicles.

Kevlar, which even its discoverer admits fought the odds to make it into production, ended up as the catalyst for saving the lives of countless men and women, both on battlefields as well as on the mean streets of the world's cities.

Identification right at their fingertips

Crime fighters had long been searching for an infallible method with which to identify criminals. In the 1870s, a French scientist named Alphonse Bertillon formulated a system for classifying habitual criminals by measuring certain human bones and keeping meticulous records of those measurements. The problem with Bertillon's system—which was used worldwide—was that it was cumbersome. Agencies that employed it had to keep extensive records and the measuring process itself was time intensive.

The Bertillon method remained in vogue for decades, but proved its fallibility in a case involving identical twins with the same aggregate bone measurements. The world's criminology community still lacked a foolproof method for determining criminals' identities until a British physician stepped up to the plate.

Dr. Henry Faulds noticed the patterns that human fingertips had left behind on some old pottery samples and recognized their value as identifiers. Faulds also developed a method for classifying fingerprints, but it wasn't until the 1890s that an Argentine police officer named Juan Vucetich launched the first fingerprint files (and not incidentally also made the first successful fingerprint comparison in a criminal case). Although not a scientist, Vucetich's visionary understanding of the significance of fingerprint identification was a giant leap forward in the science of identification of both criminals and ultimately, their victims.

Meanwhile, English anthropologist Sir Francis Galton, who had long studied fingerprints as a method of identification, devised the first known system for classifying them. Another of Galton's observations, that fingerprints are unique to the individual, added to their criminal justice value. In 1902 Dr. Henry Depelouze DeForrest, a surgeon with the NYPD and eventually, also the city's chief medical examiner, officially introduced the science of fingerprint identification in criminal cases to U.S. agencies. DeForrest subsequently invented a device called the dactyloscope, which recorded fingerprint patterns. Today, of course, fingerprint identification remains at U.S. law enforcement's fingertips through the digital Integrated Automated Fingerprint Identification System, maintained by the Federal Bureau of Investigation.

Reaching into evil minds

Jack the Ripper wasn't simply one of history's most notorious serial killers; his London rampage also helped jumpstart the art of criminal profiling. Physicians Thomas Bond and George Phillips analyzed the remains of the murderer's victims, as well as the crime scenes from which the bodies of the victims were recovered, and made some rough guesses as to the type of individual who might have committed the infamous Whitechapel slayings. Since the Ripper has never been conclusively identified, no one really knows how on-the-mark the two doctors were, but the art of criminal profiling—like the crimes of Jack the Ripper—have continued to fascinate both the public and law enforcement professionals.

The case that turned behavioral analysis into a true law enforcement tool was probably also one of the most vexing for the NYPD. The so-called "Mad Bomber," George Metesky, planted numerous bombs in the city, targeting landmarks such as Grand Central Station, but Metesky's first target was Consolidated Edison, the city's electric provider.
After 16 years of tracking the bomber with no luck, police turned to the New York State Assistant Commissioner of Mental Hygiene, a psychiatrist named James Brussel. Brussel studied notes and other documents connected with the case and produced a profile of the bomber. When police apprehended Metesky, Brussel's detailed profile was right on the money.

The FBI took an early interest in tying crimes to personalities and created its Behavioral Sciences Unit in 1974, but psychological professionals have sometimes differed with their approach. Since its initial inception, the unit has now added individuals with psychiatric and psychological backgrounds to the mix. Among the field's contemporary luminaries: Dr. C. Gabrielle Salfati, a pioneer in investigative psychology, and Dr. Anthony Pinizzotto, who is both a forensic psychologist at the FBI's Behavioral Science Unit and a Catholic priest.

The language of the dead

When it comes to working a homicide, there is no better partner than a good forensic pathologist. It's a science that has been hundreds of years in the perfecting, with an interesting and sometimes contentious history.

Autopsies were forbidden in many early cultures, including that of most of ancient Greece. However, one Greek physician, Herophilus (born in 335 BC) is believed to have been the first to conduct autopsies—at least in ancient Greece. Other Greek and Roman physicians after him also practiced autopsy, but the science was generally banned in Europe during the Middle Ages. On the other side of the globe, Chinese physicians practiced medicolegal investigation beginning in the Song Dynasty (960-1279).

Scholars say that European medicolegal autopsies date from 1302, when they were performed in Bologna, Italy. Executed criminals reportedly acted as the unwilling stars of these surgical events. And although many physicians in both the West and East added to the body of knowledge of medicolegal investigations, one scientist was considered the first modern pioneer of the field: Dr. Alexandre Lacassagne (1843-1924) a French doctor, professor and criminologist who authored, "The Principles and Practice of Medical Jurisprudence."

Lacassagne, who taught at the University of Lyon, is noted for working closely with other scientific disciplines (such as psychology and sociology) and believed that criminality was nurtured, not by biology, but instead by the individual's environment and experiences. He established protocols for autopsies, recognized the importance of determining when a homicide victim had been raped and was the first to link bullets to the weapons that fired them, thus kick starting the science of ballistics. [Editor's note: Those interested in reading more about Lacassagne and the birth of modern forensic medicine may wish to read Douglas Starr's excellent book, "The Killer of Little Shepherds" (Alfred A. Knopf, New York, 2010).]

There are so many excellent modern forensic pathologists that it's impossible to name them all, or even give a proper tip of the hat to their contributions, but it's not an exaggeration to say that without their efforts, homicide investigations would have remained in the Dark Ages.

The game changer: DNA

DNA, or deoxyribose nucleic acid, is probably the most misunderstood, as well as highly publicized, forensic tool in modern times. No one can deny its value; DNA has led to the exoneration of the wrongly accused and helped identify both perpetrators and victims. It's led to the solving of cold cases, resurrected hope for the families of the missing and allowed medical examiners and police to identify remains found decades ago.

The discovery of DNA took place when Friedrich Miescher, a Swiss scientist and researcher, isolated the substance in 1869. Scientists continued to study both DNA and its role in human genetics, but its form was not well understood until 1953 when two researchers, Francis Crick, an Englishman, and American James Watson, unlocked the double helix structure of the molecule. The men won the Nobel Prize for their work.

In the mid-1980s DNA typing was introduced as a complement to criminology. British geneticist Dr. Alec Jeffreys developed a method to use DNA to confirm human identity. Restriction fragment length polymorphism (RFLP), the method Jeffreys devised, was instrumental in resolving several cases, including a double homicide. The subsequent discovery by Dr. Kary Mullis that DNA could be replicated resulted in the polymerase chain reaction or PCR, which allows smaller numbers of DNA molecules to be increased in a short period of time. That meant more highly degraded evidence could be reliably analyzed for DNA.

Scientists worldwide continue to expand on the uses of DNA, but databases such as the Combined DNA Index System (CODIS) and NamUs (National Missing and Unidentified Persons System) implement current knowledge to resolve crimes and put names to faces and criminal acts.

Making tomorrow better

How many criminal investigators watching an autopsy have considered the uncountable number of hours that have gone into the historic art of determining whether a death resulted from foul play?
For many hundreds of years medical students were forbidden to dissect human bodies, giving rise to grave robbers and black market corpses. Those who studied death were pioneers in a field that often required extraordinary dedication and determination.

According to author Douglas Starr, the corpses of French murder victims in the late 1800s were often autopsied on the spot, sometimes on their own kitchen tables or in fields lit by lanterns, even in cases where the deceased had putrefied and decayed. There were no masks, no exhaust systems, no pristine autopsy tables, and no gloves or aprons to protect the physician from body fluids. The French professor, Lacassagne, dictated that doctors carrying out autopsies also digitally check for signs of anal rape in their victims.

Like other forensic sciences, forensic medicine, as those dedicated French physicians proved more than a century ago, is not for the weak-willed or easily discouraged. They are the men and women who give those who fight crime the arsenals they need to do their jobs.