Silent Witnesses (16 page)

Despite such significant developments in the use of lenses for magnification, it was not until the mid-seventeenth century that the microscope was used in Europe for in-depth scientific examination. One of the first examples is the publication of
The Fly's Eye
in 1644. This detailed study of the anatomy of insects using a microscope was by the Italian astronomer and priest Giambattista Odierna, who was self-educated in science.

However, it was another Italian, the physician and biologist Marcello Malpighi (1628–1694), who truly pioneered the use of microscopes in biological study. While examining the structure of the lungs under a microscope in 1661, he observed that the lining of the lungs contained balloon-shaped sacs (alveoli), which were in turn connected to branch-like structures leading from small arteries and veins (capillaries). This historic discovery not only explained how oxygen is moved from the lungs into the blood, but also founded the science of microscopic anatomy,
a field in which Malpighi made many significant discoveries throughout his career.

Following this, one of the greatest contributions to microscopy came from Dutch microscopist Antonie van Leeuwenhoek (1632–1723). Leeuwenhoek's fascination with developing and improving microscope lenses eventually enabled him to examine objects as small as one millionth of a meter. In 1674 he was the first man to discover single-cell organisms (now called microorganisms), including bacteria and sperm. In 1684, his advancements in microscopy enabled him to publish the first accurate observation of red blood cells. His work was confirmed by philosopher Robert Hooke (1635–1703), whose earlier work
Micrographia,
published in 1665, was widely respected for its intricate and accurate drawings of insects and organisms seen through a microscope. Leeuwenhoek's development of the microscope laid the foundations for future microbiology as well as promoting the use of microscopes for scientific study from the late seventeenth century onward.

Further improvements to the microscope came in 1893 when the German scientist August Köhler developed a method to better illuminate microscope samples. He wanted to produce high-quality photographs from a microscope but was hindered by the uneven distribution of light supplied by then-achievable methods of illumination such as gas lamps. To remedy this, he used a collector lens to focus an image of an illuminating lamp into the front focal plane of the microscope, producing an evenly illuminated field of view without optical glare. Köhler illumination is still a central process in contemporary light microscopy.

Eighteenth-century microscopes on display at the Musée des Arts et Métiers in Paris. August Köhler's methods of illumination were to radically improve the images obtainable from microscopes such as these. This technology increasingly found its way into contemporary biology and, by extension, forensic science.

In 1891, before Köhler had even invented his new method of illumination, microscopic techniques finally made their way into the field of criminal investigation with the publication of
Handbuch für Untersuchungsrichter, Polizeibeamte, Gendarmen (Handbook for Coroners, Police Officials, Military Policemen).
Written by Austrian professor and judge Hans Gross (1847–1915), this groundbreaking book laid out why examining evidence under a microscope could be a vital step in solving crime. As this was the first book to combine the two fields of microscopy and criminal investigation, Hans Gross is considered by many to be the father of criminalistics.

Gross said of the emerging field: “A large part of a criminalist's work is nothing more than a battle against lies. He has to discover the truth and must fight the lie. He meets the lie at every step.” Of course, the trick is not only recognizing a lie, but also proving that it is a lie. It is the forensic scientist's job to see through the criminal's “cleverness” and get to the truth. At times this can be extraordinarily difficult, particularly if one is dealing with a criminal of great cunning.

Gross highlights such a case, which he came across in an old record, in which a young man was believed to have burned down the house of a farmer. The young man was the prime suspect for the crime, as it was widely known that he resented the farmer and used to work at the mill opposite the farmer's home. However, having left his occupation nine months previously, he was nowhere near the farmhouse at the time of the incident. On examining the scene, the investigating officers found evidence that, while still employed at the mill, the young man had constructed a device to set fire to the farmer's home at a later time. First he had stretched a strong spring and cord across a skylight in the granary that faced the house. Securing the spring with pitch, he had then arranged flammable material and a magnifying glass underneath the cord. Nine months later, the lens caused the sun's rays to focus onto the flammable material and ignite it. This in turn ignited the cord, which snapped, causing flaming pitch to catapult from the skylight onto the farmer's house.

While the complexity of the contraption might make us suspect this story to be apocryphal, for Gross it was a prime example of it being the criminalist's role to examine the evidence, see through the criminal's ingenuity, and expose the truth.

The reason that Gross's
Handbook for Coroners, Police Officials, Military Policemen
is such an important publication in the history of forensics is that it combined in one volume information from several different fields of knowledge, including psychology and science, and presented it in such a way as to maximize its usefulness for those involved in criminal investigation. The contents also reflected the latest emerging trends in detection; by this time the work of Bertillon had lost much appeal with criminologists outside of France. Bertillon himself had been somewhat disgraced over the theft of the
Mona Lisa
in 1911; a palm print was found and Bertillon had no way of discovering whose it was, despite, as it turned out, having taken the measurements of the thief (an unbalanced Italian named Vincenzo Perugia) some years before. Gross's book placed far more emphasis on fingerprinting, and additionally pointed to the value of analysis of dust, hairs, wood fibers, and other kinds of trace evidence.

Gross went on to found the Institute of Criminalistics in 1912 (which later became the Institute of Criminology) as part of the University of Graz Law School. This was to be the first of many similar institutes opened all over the world, formalizing Gross's conception of criminalistics as a discipline in its own right.

One case that Gross investigated serves as an excellent example of the value of gathering trace evidence for analysis under a microscope. While walking their dog by the sea one day, three little girls underwent a frightening ordeal. They were accosted by a man who first exposed himself to them, then sexually assaulted them, placing his penis inside their underwear. When they returned home, terrified, they immediately informed
their parents, who called the police. The police followed standard procedure and collected all the clothing that the girls had been wearing at the time. When examined, the underwear of all three girls was found to have semen stains inside the crotch.

The following day one of the girls was out walking with her mother and was shocked to see the man who had assaulted her. The girl pointed him out and he was quickly arrested. Semen stains were discovered in and around the flies of his trousers. This seemed to confirm the girls' story but on its own was hardly conclusive proof of his guilt. However, a dog hair was also recovered from the trousers, as well as some colored wool fibers. When these were examined under a microscope, the hair turned out to be an exact match for those from the girls' terrier and the fibers to be an exact match for the dresses that the girls had been wearing. The case was proven. This was not just a triumph for justice and for Gross, but also an eloquent demonstration of the power of the microscope in dealing with trace evidence.

An unlikely leader in the field of forensic microscopy was Georg Popp (1863–1941) from Frankfurt, Germany, who had originally trained as a chemist. Although experienced in microscopic techniques from his work in laboratories, it was only in 1900 that he gained his first taste of forensic microscopy, when a criminal investigator asked him to use his expertise to examine some evidence. It was the beginning of a lifelong fascination and a career in criminology. In 1889 he even founded his own laboratory, the Institute of Forensic Chemistry and Microscopy, which dealt with toxicological scientific analysis for the purpose of criminal investigations.

Influenced by Gross's book, he was a firm believer in the importance of fingerprints and in the practice of photographing them. He was even able to use his knowledge in this area—and in chemistry—to solve a crime that had occurred in his own lab. During the course of a theft, the culprit had touched a piece of platinum. Popp exposed this to vapors of ammonium sulphohydrate which caused fingerprints to show up in black wherever the thief had touched. From these it was soon possible to identify the perpetrator as a man who used the laboratory on a regular basis.

Fingerprints were also involved in one of the first cases to bring Popp to the attention of the public, when he was instrumental in solving the murder of a piano dealer in Frankfurt—he discovered and photographed prints at the scene of the crime and then compared them with suspects until he got a match. However, the case that really made him famous revolved around trace evidence, not fingerprints.

In October 1904, a young woman named Eva Disch was found dead in a bean field in Frankfurt. The postmortem examination showed that she had been raped then strangled to death with a scarf. A stained handkerchief had been found at the scene. Popp examined it under a microscope and found nasal mucus containing traces of coal, snuff, and the mineral hornblende.

Using this evidence, a man by the name of Karl Laubach soon became the prime suspect. He was known to use snuff and worked in a coal-burning gasworks as well as part-time in a local gravel pit that contained a large quantity of hornblende. Popp examined Laubach's fingernails and found coal and grains of minerals including hornblende underneath them. On
examining Laubach's trousers, he found further evidence. Soil samples taken from them revealed two layers; the sample from the lower layer, directly in contact with the cloth, contained minerals that matched those taken from the crime scene. The upper layer contained particles of crushed mica mineral, which matched soil samples taken from the path from the murder scene to Laubach's home. Popp concluded that Laubach had picked up the first layer of minerals from the crime scene, before the layer of mica was added on top of it on his way home. Once confronted with this evidence, Laubach confessed. One of the Frankfurt newspapers of the day carried the headline “The Microscope as Detective” in homage to Popp's painstaking investigation.

Popp garnered further nationwide acclaim in 1908 when he was instrumental in bringing the murderer of a woman named Margarethe Filbert to justice. On May 29 that year, in Rockenhausen in Bavaria, an architect reported his housekeeper—Filbert—missing. She had taken a train to a nearby village the previous afternoon in order to go on a walk through the valley of Falkenstein, to see its ruined castle. She had failed to return home that evening.

After several days of searching, the police discovered her headless corpse in the woods. The initial impression given by the gruesome scene was that it had been some kind of sex crime; Filbert was lying on her back with her legs apart and her skirts pushed up. However, a later postmortem showed no sign of sexual assault. It was also noted that her purse, hat, and parasol were missing, meaning that robbery could not be ruled out as a motive. The pathologist who examined the body concluded that she had been strangled before having her head
removed using a sharp knife. Hairs were discovered in her hands.

A local magistrate, alarmed by the savagery of the crime and aware of Popp by reputation, traveled to Frankfurt to seek his guidance in the case. He quite rightly felt that the hairs might be a vital clue that would reveal the identity of the killer and asked Popp to examine the evidence. Unfortunately, Popp quickly ascertained that the hairs came from Filbert's own head. However, he was now intrigued by the case and offered to continue his investigation.

The main suspect was a local factory worker named Andreas Schlicher, who was also a poacher whom witnesses claimed they had seen near the field on the day of the crime. When questioned he became indignant, denying any involvement with the murder. When a pair of his trousers, his gun, and its ammunition were discovered at the nearby castle, he claimed to have left them there the day before the murder, saying he often did this to avoid alerting people to his poaching. Bloodstains were found on the knees of the trousers. When Popp soaked them in salt water and carried out the Uhlenhuth test, the reaction of the serum indicated that it was human blood. Further spots of blood were found on Schlicher's jacket, though it seemed that he had tried to wash them out. The evidence against him was mounting, though for the time being was still inconclusive.