The term “forensic” is derived from the Latin word “forēnsis,” which means of or before the forum. The history of this word dates back to Roman times, during which the person accused of a crime was presented before a group of individuals in the forum.
In modern times, forensic science refers to the various scientific techniques that are used to solve crimes. This involves collecting, analyzing, and presenting evidence in order to solve a crime or successfully convict the offended.
Forensic science is mostly used to
- Prove elements of a crime scene
- Detect decedents or suspects
- Establish a connection to a crime
- Verify or disprove suspect’s or victim’s statements
The increased use of advanced scientific techniques to gather and analyze evidence has led to the closure of many civil and criminal cases that couldn’t be solved via classical methods. In fact, new techniques are being applied to several-year-old cases that remain unsolved.
Many different types of forensic science exist. Each specializes in a unique field to aid in solving legal disputes or crimes. Here’s is the bird’s eye view of the different branches of forensic science.
Table of Contents
12. Computational Forensics
Computer Animation of a car accident
Use of computer-based simulation and modeling to study digital evidence
The modern crime investigation leverages the hybrid-intelligence of humans and machines. More specifically, computer software and tools allow forensic practitioners to:
- Search large amounts of data efficiently
- Reveal trace evidence for further investigation
- Examine evidence in an objective and reproducible way
- Evaluate the quality of the examination technique
- Visualize and document the result of the investigation
- Reveal hidden or previously unknown patterns
During the whole process, a broad range of substances, objects, and processes are examined. They are based on pattern evidence, such as shoeprints and toolmarks, as well as physiological and behavioral patterns.
Application of Computer animation (for example, audio-visual reconstruction of incidents to aid investigators) in courtrooms is becoming more popular these days.
11. Forensic Astronomy
Science of solving puzzles using the sky
Astronomy is used (although relatively rarely) in forensic science to determine the sky’s appearance at certain times in the past. Moon’s or Sun’s location in the sky at specific times may legally relevant, such as figuring out the date on which an image was clicked. It is mostly used to resolve issues in art history and other historical problems.
One of the leading experts in the field, Dr. Don Olson, an astrophysicist at Texas State University, has developed special computer programs that map ancient star charts with historical records, photos, weather charts, and tidal patterns. Using these computer tools, he has solved several fine arts puzzles from the past.
10. Forensic Geology
A research team studying rock 3 kilometers underground
Study of evidence, including mineral and substances, found in Earth
Geology is the science of Earth: it deals with the dynamics and physical history of the Earth, as well as chemical and biological changes that our planet has undergone or is undergoing. Forensic geology address the legal aspects and ramifications of the analysis of the Earth processes and materials.
The use of geological evidence in crime investigation originated with the fictional detective, Sherlock Holmes, in the late 1980s. However, the first real-world use of forensic geology doesn’t appear to have occurred until 1904, when German chemist Georg Popp identified a murder suspect from a handkerchief that contained traces of coal dust and the mineral hornblende.
Today, forensic geologists combine science, technology, efficient methods, and personal experience to solve issues involving soil, surface water, groundwater, and anything beneath the Earth’s surface. They use various instruments and techniques, such as scanning electron microscopes, X-ray diffraction, and microchemical analysis.
9. Forensic Seismology
Crater made in the wake of the nuclear blast
Identification and analysis of distant phenomena using seismology
In this field, various methods of seismology are used to detect and examine underground explosions, especially nuclear explosions. It plays a crucial role in the enforcement of bans on nuclear weapons.
Forensic seismology can also detect other underground events such as explosion within submarines, the movement/collision of icebergs, or massive ocean waves.
In order to accurately identify and spot detonations, a network of about 170 seismic stations is used. These stations capture underground pressure (P) waves and send this signal for processing over a secure communication channel. Special software programs then isolate patterns, eliminate noise, and calculate the explosive yield and depth of burial.
8. Digital Forensics
A hard disk drive head and platter
Recovery and analysis of material found in digital devices
Digital forensics is a science of finding evidence from digital devices. The technical aspect of an investigation can be split into several sub-fields based on the type of digital equipment involved: computer forensics, mobile device forensics, network forensics, forensic data analysis
There are five key processes in digital forensics:
- Identification: Find the evidence, noting where it is stored.
- Preservation: Isolate, secure, and preserve data so no one can tamper with the evidence.
- Analysis: Reconstruct chunks of data and draw conclusions based on the extracted information.
- Documentation: Create records of all data so it can be used to recreate the crime incident.
- Presentation: Summarize data in a way that it can be easily understood and presented/accepted in a court of law.
However, there is one major limitation in a digital forensic investigation: the use of encryption. It disrupts the initial analysis where pertinent evidence might be located. Laws to make people and companies disclose encryption keys are still relatively new and controversial.
7. Forensic Art
Presentation of visual information in relation to legal procedures
Despite several advances in high-tech investigative tools, a simple pencil sketch can have a substantial impact on civil or criminal cases. These sketches are used in the identification, apprehension, and conviction of a wanted person.
Typically, forensic artists create such images using crime scene evidence, skeletal remains, or eyewitness accounts. They work closely with law enforcement officers to identify victims and criminal suspects through facial composite sketches.
The three key disciplines in the forensic art field are:
1. Composite Art: involves sketching an unknown subject using a number of individually described parts. A final image is intended to be a likeness or similarity of a witness’s perception of the subject.
2. Image Modification: is the process of altering or enhancing photographs in order to help an investigator. Examples of this include age progression/regression or clarifying the CCTV footage to recognize a person.
3. Post-Mortem and Facial Reconstruction: involves rebuilding the facial features of either partially or fully decomposed human remains. Artists can draw or use digital software to produce 3D clay figures.
6. Forensic Entomology
Flesh fly on a decomposing flesh
Study of arthropod biology, such as insects and centipedes, to criminal matters
Although forensic entomology is mainly associated with death investigations, it can also be used to detect poisons and drugs, determine the time of the infliction of wounds, and find the location of an incident.
Right from the early phases, insects are attracted to the decomposing body and often lay eggs in it. Forensic scientists can analyze the population of insects as well as the developing larval stages to figure out the postmodern index, any alteration in the corpse position, and the cause of death.
The forensic entomology field can be further split into three categories:
- Urban: It usually focuses on pests infestations that are related to litigation, such as legal disputes between landlords and exterminators.
- Stored-product: It involves cases of insect infestation or contamination of commercially distributed foods with the purpose of finding evidence relevant for litigation.
- Medico-legal: It involves gathering evidence through the examination of insects and other arthropods at a crime scene.
The most frequently studied insects include flies, beetles, scorpionflies, mites, ants, and bees, which are often found in (or near) the body. Investigators also analyze other factors such as location, weather, and geography of the crime scene to determine the time of death.
5. Bloodstain Pattern Analysis
Examination of the shapes and distribution of patterns of bloodstains
The use of bloodstains as evidence is not something new. Since the 1960s, trained bloodstain pattern analysts have been using physics (fluid dynamics), biology, and mathematical calculations to accurately reconstruct events at the crime scene.
Analysts categorize the stains by collecting information from splash patterns, transfers, voids, and other marks. Usually, they look for
- Distance from the blood source to the target
- Nature of the force that caused the bloodshed
- Direction of travel and impact angles
- Object(s) that caused the bloodshed
- Sequencing of two or more bloodshed events
Sometimes, specifically developed software, such as HemoSpat, is used to calculate the area-of-origin of impact patterns. The software can also measure the impacts on non-orthogonal surfaces and show results from various angles.
4. Forensic Chemistry
Identification of unknown substances found at a crime scene
Forensic chemistry involves the analysis of non-biological trace evidence obtained from crime scenes. The chemist matches samples to known substances, determines the chemical makeup of the material, and discovers where it came from.
Forensic chemists spend most of their time in the lab, analyzing the evidence. They use a wide range of techniques and instruments to identify unknown substances. The two most common methods are:
- Spectroscopy: Science of measuring spectra produced when materials interact with or emit electromagnetic radiation.
- Chromatography: An analytical method for separating a mixture of chemical substance into its individual components so that those components can be thoroughly examined.
Specialists mostly use gas chromatography-mass spectrometry, thin-layer chromatography, Fourier transform infrared spectroscopy, atomic absorption spectroscopy, and high-performance liquid chromatography.
During the whole process, they follow a set of predefined rules proposed by specific agencies and governing bodies. These rules ensure the quality assurance and quality control of methodologies and instruments used in the process.
3. Election Forensics
Determine if election results are statistically normal
The consequences of electoral fraud are grave for democratic stability and quality. That’s why effective techniques are required to identify and investigate fraud in elections.
Election forensic utilizes various quantitative methodologies to verify that observed election results do not differ from normal occurring patterns. These methodologies can be simple (such as using Benford’s law to evaluate the deviation or conformance of vote counts) or can be more complicated and involve machine learning methods.
The latter provides algorithms and tools that look for abstract patterns in data. For example, by using both the synthetic data of vote count and the empirical data from controlled scenarios (where fraud has been observed), one can train the algorithm to ‘learn’ certain regularities present in the data and associate them with the existence of fraudulent manipulation.
2. Forensic Engineering
Broken fuel pipe from a road traffic accident
Analysis of failures, ranging from serviceability to catastrophic
Forensic engineering includes the investigation of structures, materials, or components that fail or do not function properly, causing damage to property or personal injury. This field also deals with retracing faulty mechanisms that lead to mishaps.
Typically, the aim of forensic engineering is to determine the facts of an accident and spot the point of failure with a view to increase longevity and enhance the performance of the component.
To achieve this, engineers mostly used two methods:
- Fault Tree Analysis: A top-down approach of examining an undesired state of a system. It can be used to perform all kinds of system-level risk assessment process.
- Failure Mode and Effects Analysis: A systematic, proactive technique for identifying location and causes of failures. It also involves evaluating the relative impact of different failures.
Airplane crashes, rail accidents, building collapses, heavy machinery failures are usually investigated by forensic engineers. Furthermore, many products have forensic components that monitor signs of early faults to improve efficiencies and quality.
1. Forensic DNA Analysis
Comparing criminal suspects’ profiles to DNA evidence
DNA evidence alone isn’t enough to secure a conviction, but it has become the gold standard in forensic science. It has gotten progressively accurate and faster in the last three decades.
DNA analysts retrieve data from skin cells left behind on a crime scene and conduct tests in a laboratory with dedicated facilities and devices that meet the FBI’s Quality Assurance Standards for Forensic DNA.
The majority of the DNA samples submitted to a lab undergo a sequence of a predefined process, which involves extraction, quantification, amplification, separation, analysis, interpretation of DNA profiles.
Modern data analysis techniques have made it easier to detect and distinguish individuals from a mixed DNA sample. Scientists are currently exploring new DNA methods and user-friendly equipment that could make it possible to run and examine samples in less than two hours.