Crimes,  DNA,  Forensics,  Genetics

Serving Justice: An Overview Of Forensic Science

Forensic science helps solve crimes

Forensic science is a polymorphous discipline that uses science and technology to solve crimes and bring tangible evidence to justice. It encompasses a variety of scientific fields, some of which are relatively unknown to the general public. In the twenty-first century, forensic science is now crucial to the conduct of criminal investigations and the smooth running of the judicial process. In this article, we provide an overview of the various disciplines involved in forensic science.

Forensic anthropology: a key discipline in the identification of human remains and the analysis of trauma

Forensic anthropology is a branch of physical anthropology that focuses on the application of knowledge of anatomy, physiology and pathology to legal and forensic issues. This discipline is often used to identify human remains, determine causes of death, assess injuries and trauma, and help solve crimes. Here are just a few examples of forensic anthropology’s areas of application:

  • Identification of human remains: forensic anthropologists can help identify human remains by examining physical characteristics such as size, skull shape, teeth and bones. They can also use dating techniques to determine the age of the remains
  • Determining cause of death: forensic anthropologists can help determine cause of death by examining injuries and trauma to the body. They can also examine body tissues and fluids for signs of disease or poisoning
  • Injury and trauma assessment: forensic anthropologists can help assess injury and trauma by examining bone and soft tissue. They can also use medical imaging techniques to visualize internal injuries

Forensic anthropology is an important discipline that can help solve crimes, identify human remains and determine causes of death. Forensic anthropologists use knowledge of anatomy, physiology and pathology to help solve legal and forensic questions.

Forensic pathology or dispelling the mysteries of death

Forensic pathology is a discipline that plays a crucial role in solving crimes. It helps determine the cause of a person’s death and provides forensic evidence that can be used in court. Here are some key elements of forensic pathology:

  • Forensic autopsy: carried out at the request of the public prosecutor or by order of a board of inquiry. It identifies the cause of death and determines whether it was due to natural causes or human intervention
  • Forensic medicine: its aim is to resolve all medical questions concerning the rights and duties of human beings in society. It can be used to determine a person’s age, to assess the physical damage suffered by a victim, or to establish an individual’s criminal liability
  • Psychiatric expertise: this is systematically used in the criminal justice system to assess an individual’s criminal responsibility. It is based on an assessment of the mental health of the alleged perpetrator
  • New investigative methods: forensic pathology is constantly evolving, with the emergence of new technologies and new investigative methods. For example, the use of DNA now makes it possible to identify suspects with a high degree of precision

Fingerprinting, when fingerprints lead to the killer

Fingerprinting is an identification technique that involves comparing a person’s fingerprints with those found at a crime scene or in a database. The challenges of fingerprinting are many and varied:

  • Identification of criminals: fingerprinting is used to identify criminals by comparing fingerprints found at a crime scene with those of suspects
  • Victim identification: fingerprints can also be used to identify victims of crime or natural disasters
  • Crime prevention: fingerprinting can help prevent crime by identifying repeat offenders and preventing them from committing new offences
  • Evidence reliability: fingerprints are considered reliable evidence in court, as they are unique to each individual and cannot be easily falsified
  • Development of new technologies: Fingerprinting has led to the development of new identification technologies, such as facial and voice recognition

Developed in 1902 by Alphonse Bertillon, fingerprinting remains an essential identification technique for the police and the judiciary, helping to identify criminals, prevent crime and guarantee the reliability of evidence in court.

Ballistics, the study of projectiles and their movements

Ballistics is a branch of physics that studies the movement of projectiles and their behavior in air and other media. Here are some key elements of ballistics science:

Gun loaded with two bullets
  • Trajectory: the trajectory of a projectile is the curve it follows in air or another medium. It is influenced by factors such as initial velocity, gravity, air resistance and projectile shape
  • Range: the range of a projectile is the distance it travels before hitting a target or falling to the ground. It depends on muzzle velocity, firing angle and target height. Trajectory and range make up external ballistics
  • Internal ballistics: internal ballistics is the study of projectile movement inside the firearm. It takes into account factors such as gas pressure, muzzle velocity and projectile stability
  • Terminal ballistics: terminal ballistics is the study of the behavior of a projectile when it hits a target. It takes into account factors such as penetration, expansion and fragmentation

Ballistics is used in forensic science to elucidate the circumstances of a firearm shooting. It is used to determine the trajectory of the projectile, the firing distance and the weapon used.

Toxicology, the study of substances harmful to the body

Forensic toxicology is the study of the effects of toxic substances on the human body and their role in solving crimes. It is used to determine whether a person has been exposed to toxic substances and whether this has contributed to death or injury. Here are some key elements of forensic toxicology:

Toxicology analyzes toxic substances
  • Toxicological analysis: this is performed on biological samples such as blood, urine or hair to detect the presence of toxic substances in the body
  • Identification of toxic substances: forensic toxicologists use sophisticated analytical techniques to identify toxic substances present in biological samples
  • Interpretation of results: the results of toxicological analysis are interpreted to determine whether the presence of toxic substances contributed to the person’s death or injury
  • Expertise in court: forensic toxicologists may be called to testify in court to explain the results of their conclusions

Forensic toxicology is an important discipline in crime solving, as it can provide crucial evidence to identify culprits and victims. It is also used to assess the health risks associated with exposure to toxic substances in the environment.

Forensic entomology, the analysis of interactions between insect squads and cadavers

Forensic entomology is a scientific discipline that uses the study of insects to help solve crimes. Insects can provide valuable information on the time of death, the place where the body was found and even the cause of death. Here are some key elements of forensic entomology:

  • Colonizing insects: colonizing insects are the first to arrive on a body after death. They can be used to estimate the time of death, as their life cycle is well known and can be used to determine how long the body has been exposed to the environment
  • Necrophagous insects: necrophagous insects feed on dead tissue and can be used to determine the time of death depending on where the body was found. Necrophagous insect species vary according to geographical region and environmental conditions
  • Predatory insects: predatory insects feed on other insects and can be used to determine the time of death and the place where the murder took place. Predatory insect species also vary according to geographical region and environmental conditions

Forensic entomology is often used in conjunction with other scientific disciplines, such as forensic medicine and forensic science, to help solve crimes. Forensic entomology experts may be called to testify as expert witnesses in criminal trials.

Bloodstains pattern analysis: when blood spatters are rich in information

Bloodstains pattern analysis is a crime analysis technique that identifies the morphological characteristics of bloodstains. This technique is used to determine the nature of the wound, the angle of impact, the direction of movement and the position of the victim or assailant.

Bloodstains pattern analysis is a forensic science

Bloodstains pattern analysis is based on the observation of bloodstain shapes and patterns, and the analysis of their size, shape and distribution. This technique is used in criminal investigations to help reconstruct the events that led to the presence of bloodstains at a crime scene.

Bloodstains pattern analysis is an accurate and reliable technique that can provide important information for solving violent crimes. However, it must be used with caution and by trained experts to avoid misinterpretation and erroneous conclusions.

Forensic odontology: teeth and identity

Forensic odontology is a branch of forensic medicine that uses dental knowledge to solve crimes. In France, the history of forensic odontology dates back to 981, when Hugues Capet, then Duke of the Franks, went to Rome and brought back with him the relics of Saint Columba. The relics were examined by a dentist, who was able to identify the teeth as those of a woman.

Forensic odontology studies teeth and gums

Since then, forensic odontology has been used to identify victims of crime, particularly when bodies are so decomposed or burnt that they are no longer recognizable. Dentists can also help determine a person’s age, sex, race and eating habits from their teeth.

Forensic odontology is also used to identify bites on victims or suspects, which can be compared with the suspects’ dental impressions to determine whether they bit the victim. Dentists can also help determine cause of death by examining the victim’s teeth and gums.

Dentists practicing forensic odontology must follow strict quality criteria to guarantee the accuracy of their findings. Forensic odontology is also used to identify victims of natural disasters or armed conflicts.

To sum up, forensic odontology is an important discipline in crime solving, particularly in identifying victims and suspects.

DNA identification, the star of forensic science

DNA identification has become a decisive tool in solving crimes. DNA is unique to each individual, making it possible to use it as evidence to convict a person suspected of an offence, or to exonerate an innocent person.

Samples taken from crime scenes or suspects, usually from blood, hair or body fluids, are analyzed to establish a DNA profile and compare it with other DNA profiles stored in a database.

Police can submit DNA profiles of offenders, missing persons, unidentified human remains, or profiles taken from crime scenes, and get a search result within minutes.

DNA sampling, amplification and analysis methods have also been perfected, enabling DNA fragments to be found in traces taken from the scene of the crime, such as door handles or clothing, even after many years.

DNA testing is a cornerstone of modern forensics, and has played a decisive role in a number of landmark trials. In 1983 and 1985, two 15-year-old girls were murdered in the UK. The police arrest a suspect, but he denies having committed the crimes. The police are in possession of semen samples found at the crime scenes. They contact Alec Jeffreys, the geneticist who has developed DNA fingerprinting techniques, to see if his method can help the police prove the suspect’s guilt. The first genetic profiling was carried out, and the discovery led to the publication of an article in Nature magazine in March 1985. It’s the first crime solved using DNA testing.

Genetic genealogy is also increasingly used to solve unsolved crimes (see our article Why is genetic genealogy revolutionizing crime solving?). This method involves comparing the results of genetic analysis of DNA found at a crime scene with genealogical databases to find distant relatives of the suspect. However, this method raises questions of ethics and police deontology.

Forensic geology, the study of soil and terrain

Forensic geology is a discipline that uses geological knowledge to solve crimes. It is a branch of forensic science, which is the set of techniques used to establish proof of a crime. Forensic geology is particularly useful for the study of traces and clues at crime scenes and in the laboratory. Here are just a few examples of how forensic geology has been used to solve crimes:

Rocks and forensic geology
  • Soil and rock analysis: forensic geology experts can analyze soil and rocks found at the crime scene to determine their geographical origin. This information can help identify where the crime was committed, or link crimes committed in different locations
  • Mineral and metal analysis: forensic geology experts can also analyze minerals and metals found at the crime scene to determine their geographical origin
  • Pollutant analysis: forensic geology experts can analyze pollutants found at crime scenes to determine their origin and impact on human health. This information can help identify the causes of death or illness in victims
  • Fossil dating: forensic geology experts can use fossil dating to determine the age of human remains found at crime scenes. This information can help identify victims and link crimes committed at different times

Forensic geology is a constantly evolving discipline, and new techniques are regularly developed to help solve crimes. Forensic geology experts often work in collaboration with other scientific specialists, such as medical examiners and ballistics experts, to provide solid evidence in criminal investigations.

Trace analysis: making shoe and vehicle prints talk

The analysis of tire tracks and shoe soles can be a crucial element in solving criminal cases. Here’s some information on the use of tire and shoe treads in criminal investigations:

Shoe prints and trace analysis
  • Tire tracks can be used to determine the type of vehicle involved in a crime, as well as the make and model of tire. Experts can also determine tire pressure, vehicle speed and direction of travel
  • Traces of shoe soles can be used to identify suspects. Experts can compare shoeprints found at crime scenes with suspects’ shoes to determine whether they match
  • Experts can also use comparison software to analyze tire tracks and shoe soles. This software can help identify tire and shoe makes and models, as well as compare prints with those of suspects

The analysis of tire tracks and shoe soles can be a differentiating factor in solving criminal cases. Experts can use these tracks to identify the vehicles involved in a crime, determine the direction in which they were heading, and identify suspects. Comparison software can also help speed up the analysis process.

Forensic computing, the delicate balance between ethics and technology

Forensic computing is a discipline that uses information technology to help solve crimes. It has become increasingly important in modern criminal investigations. Digital tools are used to collect, analyze and interpret digital evidence, such as cell phone data, CCTV recordings and computer data. Forensic computer experts can help identify perpetrators, trace firearms and confound criminals.

Digital forensics is a branch of forensic science that uses digital technologies to help solve crimes. It can help bring investigative work from crime scenes into the real world. Digital tools can be used to collect evidence, analyze data and help identify perpetrators.

Forensic scientists can use digital tools for their research into genetics, anthropology, morphoanalysis of blood traces, forensic fauna and flora, weapons and explosives, etc., to help solve criminal cases. Forensic pathologists can also help to produce forensic summaries of exhibits, popularizing often lengthy and complex medical reports.


Male feet and forensic podology

Forensic disciplines play a key role in solving criminal cases. Forensic evidence can provide valuable information about the circumstances surrounding a crime, help identify perpetrators and victims, and contribute to the conviction of the guilty. In addition to the fields presented in this article, forensic science has seen the addition of other areas of research over the years, such as linguistics and forensic podology (footprints).

However, it is important to note that forensic evidence is not infallible and can be subject to error. For this reason, it is essential that forensic experts are properly trained, and that expert reports are written clearly and precisely, mentioning the limitations of the conclusions drawn.

The use of appropriate forensic vocabulary is important to avoid misunderstandings and misinterpretations. In summary, forensic disciplines are a valuable tool in solving criminal cases, but their use must be supervised and their reliability carefully assessed.

Read the article in French

Leave a Reply

Your email address will not be published. Required fields are marked *