What Is Forensic Science?

Forensic science is the application of scientific methods across civil and criminal law. The best-known types of forensic science are around the analysis and interpretation of evidence in order to solve crimes and bring successful prosecution of criminals. Forensic science is a highly competitive field with entry requiring undergraduate and potentially postgraduate degree qualifications. 

With the spread of the CSI (Crime Scene Investigation) series and similar TV shows, forensic science has become hot property, leading to a surge of public interest in forensics and the role scientists can play in police investigations and legal proceedings. If you’d like to learn more about forensic science in the real world, or how to become a forensic scientist, then this is the article for you.

What does a forensic scientist do?

The core of a forensic scientist’s job is to gather and analyze scientific evidence to help solve crimes (or prove legal points in civil prosecutions). Forensic scientists must work in alignment with national rules on admissible evidence and due legal process in order to ensure that their findings and conclusions are admissible in a court of law.

Not every forensic scientist gets directly involved with crime scene investigation in the field and some are largely laboratory-based. Examples of normal forensic science work might include:

  • collecting trace evidence and recording environmental findings at the scenes of crimes and accidents,
  • coordinating work with the police and other agencies involved in criminal or civil investigations,
  • laboratory analysis of biological and chemical samples (e.g. hair, body fluids, paint, drugs),
  • applying advanced analytical techniques to samples, such as gas or high-performance liquid chromatography, genetic fingerprinting, scanning electron microscopy, mass spectrometry, infrared spectroscopy,
  • interpreting and writing up analytical results and computer data,
  • giving oral evidence in court, including justifying your analysis and conclusions under cross-examination,
  • researching and developing new forensic science methods and techniques.

What are the different areas of forensic science?

There are numerous different branches and specializations within forensic science. (For example, the American Academy of Forensic Sciences organizes its 7000 members into eleven sections representing  various areas of member interest, activity, education or expertise.)

A few of the principle branches are detailed in this section.

Forensic chemistry

Forensic chemists might be involved in work such as analyzing samples of paint, accelerants or other chemicals from crime scenes related to burglary, arson, car accidents etc… Findings could help to inform fire investigations and reconstruction of incidents.

Forensic biology

Forensic biologists will often work on investigation of crimes against people (e.g. murder, rape, physical assault), carrying out DNA testing and biological contact traces of blood, hair or textile fibers.

Forensic pharmacology and toxicology

In forensic pharmacology and toxicology, scientists may be examining tissue or body fluid examples for poison or restricted drugs, for example, testing blood and urine samples for alcohol in suspected drink-driving offenses.

How is forensic science used?

Forensic science has many uses.

It can establish the identity of victims, perpetrators and sometimes witnesses of crimes, using DNA and other trace analysis, along with dental records, fingerprint and other physical evidence.

At the same time, it can produce evidence that a particular person, vehicle or object were present at a crime scene, or present at a different location, potentially clearing them of suspicion. Perhaps forensic techniques can even to be used to work out the time at which a crime or other event occurred, or determine exactly how an object or weapon was held or employed.

There is also an important role for forensic science to play in helping to reconstruct the course of an incident. For example. deducing and proving how a fire started and spread may allow police to decide whether they are investigating a case of accidental fire or deliberate arson.

Furthermore, forensic science might either disprove or corroborate witness accounts, or make links between one crime scene and another, shedding potential light on serial criminals or crime patterns.

When was forensic science developed? 

While exciting modern technologies such as DNA sequencing and ballistics modeling are often the public face of forensic science, the roots of forensics go back thousands of words. The term “forensic” itself is derived from the Latin word “forensis” meaning “of or before the forum”, originally referring to the examination of a question or issue in public.

From the use of bloody handprints to exonerate a blind man accused of murder in 2nd century Rome, to comparisons of burned pig and human corpses to reveal murder in 3rd century China, some lines of forensic science thought are truly ancient.

Timelines of forensic science history show us the development of key thinking around fingerprints, blood traces, body temperature and crucial areas over time. The 19th century in particular saw a number of important forensics leaps, for example around use of finger-printing, ballistics analysis and photography in crime scene analysis and case solving.

The history of forensic science is a long chain of experimentation, inductive and deductive thinking. This laid foundations for the advanced technological testing and computer-powered analysis used in forensic science today.

How reliable is forensic science? 

While forensic science is critical to the fair implementation of justice, it is also an extremely complex and varied field, taking in methodologies and technologies from DNA sequencing, through chemical analysis, to pattern recognition.

Many modern techniques are highly accurate and highly reliable although nothing is usually 100% certain in forensic science or any other field. Findings are often quoted by experts with a qualifying probability. For example, where a DNA match has been identified, scientists might state that there’s only a 1 in 5 million chance of that sample belonging to someone other than the suspect.)

However, a number of older forensic science methodologies were originally developed within the context of law enforcement and legal practice which may accept arguments based on precedent rather than empirical validation. This is in contrast with other sciences which typically may have developed with far greater scientific scrutiny and testing of validity. 

Exoneration of convicted criminals based on DNA forensics since the 1990s has shown major problems and weaknesses with certain forensic disciplines used to secure convictions in earlier decades (e.g. bite mark analysis for identification). Bite mark evidence may still be accepted in US courts due to legal precedent even though bite mark identification has been scientifically discredited and linked to proven false convictions.

In many countries this discrepancy has led to calls for greater scientific rigor in forensic science and major reform of its applications.

How can I become a forensic scientist?

To work as a forensic scientist you’ll usually need to complete a degree in a relevant science subject (e.g. biology, chemistry) or in forensic science itself. Subjects such as geology or statistics and might also be useful for entry into forensic specialisms.

Competition for forensic science jobs is intense and a Masters degree or PhD in a forensic science-linked subject (e.g. forensic archeology) could be what you need to make you stand out from the rest of the field.

Personal qualities required in a good forensic scientist include intellectual curiosity, sharp observation skills, and competent note-taking ability.

A final word… 

Forensic science is a fascinating and valuable discipline with a long, international history. Without accurate and credible forensic science, justice and understanding of crime would be significantly weakened.