Popular TV series like CSI Miami have done much to increase public awareness of forensic crime and the techniques now used to catch criminals
The partially clothed body of an unidentified woman is discovered on the front lawn of a house in a quiet, respectable suburban neighbourhood of Florida on a Sunday morning by a man walking his dog. The police are called to the scene, which they secure with yellow perimeter tape printed with the warning 'Crime Scene – Do Not Cross'. An officer ushers the swelling crowd of curious onlookers to the other side of the street, his partner radioing in for a homicide detective and a team of forensic investigators to comb the area for evidence.
The scene will be familiar to regular viewers of the popular US TV series CSI – Crime Scene Investigation, which pulls in an audience of more than 50 million in the US and millions more around the world. But this particular crime was real, one of many thousands of homicides reported every day of the year in towns and cities across the globe. The language and the uniforms may differ depending on the country but, sadly, murder is universal and a feature of life that goes all the way back to the day when Cain killed Abel.
Popular TV series like CSI Miami have done much to increase public awareness of forensic crime and the techniques now used to catch criminals
Chalk markings on the road record the location of bullet casings
MODERN FORENSICS
In the past the authorities have had to rely on fingerprints, eye witnesses and occasionally the culprit's compulsion to confess, but in recent years forensic science has made incredible advances with the advent of DNA analysis and trace evidence identification techniques that have given investigators what appear to be infallible tools for identifying the guilty and putting them where they belong – behind bars.
In the fictional TV show a single hair, fibre or flake of paint is sufficient to identify the killer, arsonist, robber, rapist or terrorist and place them at the crime scene. With their gleaming laboratory and state-of-the-art, high-tech diagnostic equipment at their disposal, it is usually only a matter of hours before one of the glamorous CSI techs matches the fatal bullet to the suspect's gun or reveals the full history of the deceased from a single hair, leaving the detective in charge of the case to take the 'perp' into custody as the closing credits roll.
If only it were that easy in real life, all the criminals would be in handcuffs and law-abiding citizens could sleep soundly in their beds. While it is true that 'the evidence never lies' and that a single fibre is often sufficient grounds to secure a search warrant or make an arrest, rarely is one item of evidence enough to send someone to jail or the electric chair. In the real world the law demands irrefutable physical evidence backed up by eye-witness testimony and preferably a confession too, if a conviction is to be secured. However, suspects are rarely as cooperative in real life as they appear to be on TV. They don't give up their liberty without a fight and the police never underestimate the ability of a smart lawyer to undermine witness testimony and discredit evidence in the hope of raising the spectre of 'reasonable doubt'.
The sterile atmosphere of a forensic science lab
Fortunately forensic science is continually developing, making it increasingly difficult for criminals to get away with their crimes. But unlike their elegant, ever-active fictional counterparts, the real CSIs – crime scene investigators – rarely get the chance to confront a suspect unless they are called to testify in court. Many are laboratory technicians who specialize in one area of forensic science. Forensic biologists scrutinize human trace evidence such as blood, hair and saliva. Forensic chemists analyze chemical residue for traces of drugs, explosives, paint and so forth. Forensic anthropologists can evaluate the sex, age and identity of a person from their bones and there are even forensic meteorologists who can supply vital clues regarding the weather at the crime site at a given time or day. When there are no eye witnesses, science can become the silent witness which places a criminal at the scene of the crime. A notable example can be the car which carries traces of mud from the location or is found in the killer's garage covered in rain droplets although it hasn't rained in his neighbourhood for days, but has done so miles away at the scene of the crime.
Unfortunately, although procedural police shows have increased public awareness of forensic techniques they have not dissuaded habitual criminals, and it could be argued that it has actually created an unrealistic expectation in the public mind regarding the speed and infallibility of forensic detection. It must be remembered that CODIS, the criminal database, can only produce a positive match if a criminal's DNA or fingerprints are in the system. A killer without a record remains anonymous and at large. As one forensic expert ruefully admitted, 'We have an imperfect human being using imperfect science striving for a perfect conclusion.' Killers can elude the police for years until they make a fatal error, or are caught in the act by chance because they reoffend. It is only then that all the carpet fibres, fingerprints, flakes of paint and other forensic evidence can be presented in the hope of forcing the perpetrator to confess to their crimes or cut a deal with detectives to give up their accomplices, or offer leads in other cases, if they have any.
THE REALITY OF FORENSICS
Nevertheless, thanks to the popularity of CSI and the many true crime shows which have sprung up in its wake, forensic science is now the fashionable career choice. Applications have reached record levels in every country where a college or academy is offering courses. But when they graduate, today's students will discover that real CSIs have a far harder time cracking cases than their TV counterparts. They won't be questioning suspects, nor swarming over a crime scene in Beverley Hills in Nike trainers. They will spend most of their time in the laboratory pouring over reference books, peering down microscopes and conducting mundane, repetitive tests. And although technical advances will enable them to identify the component parts of even the most minute trace evidence, they could wait weeks or even months for a test result if the laboratory is overwhelmed, as is frequently the case.
For example, at the Los Angeles County Coroner's Office, the world's largest forensic facility, a staff of 64 process 8,000–10,000 bodies a year, 24 hours a day, 364 days a year. Under such pressure it is perhaps no surprise that investigators are forced to prioritize their cases and that many freely admit that the sheer scale of the problem and lack of human resources means that many criminals are literally getting away with murder. Frequently forensic science helps to convict a guilty person only after they have made the one crucial mistake which has brought them to the attention of the police. Law enforcement now has extraordinarily sophisticated tools to help solve the puzzle posed by the crime scene, but even those at the cutting edge of the new technology admit that there are times when science is no substitute for old-fashioned, dogged detective work.
EXAMINING A CRIMINAL INVESTIGATION
In the following pages we go behind the scenes of a criminal investigation, putting the once secret science of forensic detection under the microscope. You will discover how evidence is collected and analyzed, what clues can be obtained from a crime scene and a corpse, what happens at an autopsy and how computer technology is being used in the worldwide crusade against crime. Specific forensic techniques are described in detail, including how a pathologist accurately determines the time and cause of death and how anonymous victims can be identified from a pile of bones.
At any one time, the main crypt at LA County Coroner's Office is full to overflowing
We also reveal how a medical examiner can tell whether the body on the mortuary slab has died of natural causes, or as a result of suicide, accident or foul play – and what part blood splatter, ballistics and computer programs play in re-creating the crime scene.
There is inevitably a heavy emphasis on murder cases because they are the most serious crimes a person can commit and they frequently stretch the resources and resourcefulness of investigators. However, every major category of crime is covered including arson, abduction, rape, robbery and terrorism as well as tragic accidents involving loss of life and cases in which forensic science was used to overturn a wrongful conviction and expose a serious miscarriage of justice.
If you want to know exactly how DNA, toxicology, trace evidence analysis and forensic entomology can break an apparently airtight alibi, you will find it here, where each aspect of the investigation is illustrated by real cases taken from the files of law enforcement agencies around the world, many of them appearing in print for the very first time. And if you actually do have a serious interest in becoming a real CSI yourself, this book should prepare you for what you can expect to deal with in the hard but rewarding world of forensic science.
Be warned that there is no easy route – you will normally need multiple degrees in several sciences as well as a thorough medical knowledge and, needless to say, a strong stomach. But if you can remain detached and dedicated to uncovering the facts you could find yourself contributing to the solution of baffling crimes, while making society far safer by proving the guilt of dangerous criminals and perhaps even bringing closure to bereaved families.