Detective fiction today, be it on page or on screen, has changed a great deal since the days of the ‘classic’ detectives. They were investigators who solved crimes by relying on their intelligence and keen observation and instincts to unravel a crime scene, read the clues and arrive at the truth.
FORENSIC
TECHNIQUES
REAL-WORLD
Over the past century, real-world advances in science such as forensic analysis, DNA and criminal psychology, have gone on to change the face of modern policing beyond recognition. These advances had a direct impact on crime writers who often call upon forensic experts to ensure that their stories are authentic and technically accurate.
With fiction reflecting real-life procedures and techniques, crime scene investigators and forensic scientists have a crucial role to play, by providing evidence to investigators in the pursuit of justice. We take a look here at some of their methods and techniques.
Detective fiction today, be it on page or on screen, has changed a great deal since the days of the ‘classic’ detectives. They were investigators who solved crimes by relying on their intelligence and keen observation and instincts to unravel a crime scene, read the clues and arrive at the truth.
Over the past century, real-world advances in science such as forensic analysis, DNA and criminal psychology, have gone on to change the face of modern policing beyond recognition. These advances had a direct impact on crime writers who often call upon forensic experts to ensure that their stories are authentic and technically accurate.
With fiction reflecting real-life procedures and techniques, crime scene investigators and forensic scientists have a crucial role to play, by providing evidence to investigators in the pursuit of justice. We take a look here at some of their methods and techniques.
THE CRIME SCENE
Often one of the first professionals at the scene of a crime (after first responders) is the crime scene investigator. Their task is to examine the location and gather evidence relevant to the investigation, including physical evidence and photographs. The evidence is sent to a laboratory where a forensic scientist will analyse what has been provided using a variety of scientific methods. Crimes scenes are sealed off to the public to avoid evidence loss or contamination, and allow forensic teams time and space to work.
COLLECTING EVIDENCE
There are many types of evidence that can help an investigator make decisions during a case. Some evidence might not be admissible in court, but can still be valuable in building an overall picture and reaching a conclusion. Physical Evidence: a recovered object or imprints, Character Evidence: a person’s behaviour, Digital Evidence: from an electronic source, Direct Evidence: testimony of a witness or CCTV. These are all examples of types of possible evidence.
THE CRIME SCENE
Often one of the first professionals at the scene of a crime (after first responders) is the crime scene investigator. Their task is to examine the location and gather evidence relevant to the investigation, including physical evidence and photographs. The evidence is sent to a laboratory where a forensic scientist will analyse what has been provided using a variety of scientific methods. Crimes scenes are sealed off to the public to avoid evidence loss or contamination, and allow forensic teams time and space to work.
COLLECTING EVIDENCE
There are many types of evidence that can help an investigator make decisions during a case. Some evidence might not be admissible in court, but can still be valuable in building an overall picture and reaching a conclusion. Physical Evidence: a recovered object or imprints, Character Evidence: a person’s behaviour, Digital Evidence: from an electronic source, Direct Evidence: testimony of a witness or CCTV. These are all examples of types of possible evidence.
DNA PROFILING
DNA profiling has become the gold standard of forensic science since the first case 30 years ago. To obtain a DNA profile, investigators collect items that could have been touched or worn by persons involved in a crime. Traces of biological material such as blood, saliva or hair is collected and analysed to produce a unique DNA profile of an individual.
The technique has got progressively faster and more sensitive and today investigators can retrieve DNA profiles from skin cells when a criminal merely touches a surface. This improved sensitivity combined with advances in data analysis has made it possible to identify and distinguish individuals quicker and more efficiently than ever before.
AUTOPSY
A death in sudden or unexplained circumstances requires a forensic pathologist to examine the body at the crime scene, before its removal to the mortuary for an autopsy. The word comes from Greek words meaning ‘to see for oneself’. A post-mortem examination is performed on the corpse by a medical examiner who attempts to establish the circumstances surrounding the cause of death or the identity of the deceased.
BALLISTICS
Ballistics is a branch of forensics that seeks to determine from which firearm a bullet or cartridge has been discharged, through identification of unique markings that each firearm imprints on a bullet’s surface or cartridge casing. Ballistic experts also examine the amount of damage a bullet has sustained upon hitting a hard surface to help determine where the shooter was standing, what angle the gun was fired from, and when the gun was fired.
ALTERNATIVE LIGHT SOURCE (ALS)
Crime scenes and physical evidence are subject to analysis by an Alternate Light Source. ALS devices emit light in the visible and ultraviolet regions of the electromagnetic spectrum. This light causes certain materials to fluoresce, which enhances the ability to visualise evidence using a filter, such as goggles or a digital camera. ALS devices detect a wide variety of evidence often not visible to the human eye, such as hairs and fibres, body fluids, and even gunshot residue.
BALLISTICS
Ballistics is a branch of forensics that seeks to determine from which firearm a bullet or cartridge has been discharged, through identification of unique markings that each firearm imprints on a bullet’s surface or cartridge casing. Ballistic experts also examine the amount of damage a bullet has sustained upon hitting a hard surface to help determine where the shooter was standing, what angle the gun was fired from, and when the gun was fired.
ALTERNATIVE LIGHT SOURCE (ALS)
Crime scenes and physical evidence are subject to analysis by an Alternate Light Source. ALS devices emit light in the visible and ultraviolet regions of the electromagnetic spectrum. This light causes certain materials to fluoresce, which enhances the ability to visualise evidence using a filter, such as goggles or a digital camera. ALS devices detect a wide variety of evidence often not visible to the human eye, such as hairs and fibres, body fluids, and even gunshot residue.
MASS SPECTROMETRY
One of the forensic chemist’s most commonly used and important tools is the Mass Spectrometer, a machine that can be used to chemically identify a substance essentially based on its molecular mass and charge. Trace evidence is passed through a spectrometer to discover and identify the existence of elements found in drugs, explosives, dyes and other substances helping identify possible links between a suspect and a crime scene.
Above: A scientist operates a Mass Spectrometer machine in the lab.
DIGITAL FORENSICS
Digital forensics, also known as computer forensics, is the process of analysing any type of computing device such as mobile phones, laptops, tablets or data storage. The ultimate goal of digital forensics is to identify, acquire and preserve any digital evidence that can be used to aid a police investigation. An example of digital forensics would be the analysis of a suspect’s mobile phone which might reveal an incriminating trail of digital evidence stored in the memory: messages, images, browsing history or GPS track logs which record the location of the device.
MASS SPECTROMETRY
One of the forensic chemist’s most commonly used and important tools is the Mass Spectrometer, a machine that can be used to chemically identify a substance essentially based on its molecular mass and charge. Trace evidence is passed through a spectrometer to discover and identify the existence of elements found in drugs, explosives, dyes and other substances helping identify possible links between a suspect and a crime scene.
Above: A scientist operates a Mass Spectrometer machine in the lab.
DIGITAL FORENSICS
Digital forensics, also known as computer forensics, is the process of analysing any type of computing device such as mobile phones, laptops, tablets or data storage. The ultimate goal of digital forensics is to identify, acquire and preserve any digital evidence that can be used to aid a police investigation. An example of digital forensics would be the analysis of a suspect’s mobile phone which might reveal an incriminating trail of digital evidence stored in the memory: messages, images, browsing history or GPS track logs which record the location of the device.
TECHNIQUES OF THE FUTURE
A crime scene lacking in trace evidence can leave investigators with little to go on, however scientists are exploring how we may leave other, less human clues behind. This includes bacterial traces that people leave on every surface they touch, and even in the air they breathe.
Research suggests that humans have bacterial collections that may be unique to each of us which we carry and leave behind wherever we go. Scientists are working on ways to obtain, interrogate and utilise bacterial traces in criminal investigations.
TECHNIQUES OF THE FUTURE
A crime scene lacking in trace evidence can leave investigators with little to go on, however scientists are exploring how we may leave other, less human clues behind. This includes bacterial traces that people leave on every surface they touch, and even in the air they breathe.
Research suggests that humans have bacterial collections that may be unique to each of us which we carry and leave behind wherever we go. Scientists are working on ways to obtain, interrogate and utilise bacterial traces in criminal investigations.
