Forensic Fact of the Day

Interesting and or unusual facts for those whose day starts when someone else's ends.  

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Day 35 - Fractures or broken bones are described by their location, how the bones are aligned, whether there are associated complications with blood and nerve function, and whether the skin is intact at the injury site.

Bones are rigid, but they do bend or "give" somewhat when an outside force is applied. However, if the force is too great, the bones will break, just as a plastic ruler breaks when it is bent too far. Thus, the severity of a fracture usually depends on the force that caused the break. 

These breaks are classified by where they’re open fractures (complex fractures) or closed (simple fractures). Essentially, open fractures refer to when the bone penetrates through the skin and has a higher risk of infection whereas closed fails to breach the skin. 

Simple fractures include:

Greenstick fracture: an incomplete fracture in which the bone is bent. This type of fracture occurs most often in children.

Transverse fracture: a fracture at a right angle to the bone's axis.

Oblique fracture: a fracture in which the break is at an angle to the bone’s axis.

Comminuted fracture: a fracture in which the bone fragments into several pieces.

An impacted fracture: a fracture whose ends are driven into each other. This commonly occurs with arm fractures in children and is sometimes known as a buckle fracture.

Spiral fracture: a fracture that spirals or extends down the length of the bone

Bowing fracture: when the bone bends but doesn't break. This type of “fracture” is only seen in children. 

Fractures are also defined by anatomical terms to determine locations, these include:

Proximal (closer to the center of the body) and Distal (further from the center)

(Ex. the elbow is proximal to the wrist and the wrist is distal to the elbow)

Anterior (toward the front of the body) and Posterior (toward the back)

(Ex. The chest is anterior to the back and the back is posterior to the chest)

Medial (toward the middle of the body) and Lateral (to the outer edge of the body)

(Ex. The ears are lateral to the nose and the nose is medial to the ears)

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Day 34 - Forensic photography is producing a permanent visual record of accidents and crime scenes for use as evidence in court, and for measurement and analysis.

The purpose of crime scene photography is to document what is there and where it is in relationship to the scene, whether it is obviously connected to the crime or not.

A critical aspect of photographic quality is resolution. The term resolution in the context of photography refers to the degree to which adjacent objects can be distinguished from one another in a photographic image. Obviously, the higher the degree of resolution—which is a function of the acuity of the photographic equipment used, as well as the abilities of the operator—the better the quality of the photograph.

In this line of work, forensic photographers may be expected to: 

have a thorough grasp of photographic principles, particularly those involving non-standard techniques, such as high-intensity and low-level aerial imaging

have excellent technical skills in photo imaging

appreciate the importance of your work

take a precise approach to image and data recording

be highly organised

pay close attention to detail

use the best equipment and techniques for each different environment and lighting condition

capture images that have maximum depth of field, are free from distortion and are in sharp focus

have a solid grounding in police methods

possess a sound understanding of anatomy

take images that record the appearance of physical evidence without appealing to the emotions of those judging a case

keep detailed records of the location the image was taken, the type of camera and lens used, and whether flash or artificial lights were used

have good communication skills in dealing with a wide range of professionals

demonstrate tact and discretion in dealing with victims of crime

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Day 33 - Forensic accounting is the practice of utilizing accounting, auditing, and investigative skills to assist in legal matters, such as fraud. 

A forensic accountant will seek to trace any financial discrepancies within a company's accounts and use so-called 'paper trails' or 'audit trails' to try and locate missing monies and also to find out who misappropriated them to begin with.

Forensic accounting can be divided up into 2/3 parts:

Litigation support: Factual presentation of economic issues related to existing or pending litigation (quantifies damages sustained by parties in legal matter and helps to resolve disputes before court i.e. dispute resolution*)

Investigation: act of determining whether criminal matters (employee theft, falsification of financial statements, identity theft, or insurance fraud) have occurred. 

Dispute resolution: process(es) used to resolve disputes between parties, including negotiation, mediation, arbitration, collaborative law, and litigation.*

It is important to mention also that a forensic accountant may not necessarily be employed directly by the police force investigating any wrong doings but may simply be acting as a third party - or expert witness - for the police who can call upon them if a criminal investigation goes to court.

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Day 32 - Forensic odontology (also called forensic dentistry or bitemark evidence expertise) mainly involves the identification of an assailant by comparing a record of their dentition (set of teeth) with a record of a bite mark left on a victim.

Forensic dentists (odontologists) examine the development, anatomy and any restorative dental corrections of the teeth, such as fillings, to make a comparative identification of a person.

In death cases, the forensic odontologist attends the autopsy and takes photographs, cranial measurements, dental impressions and x-rays from the remains. These samples are then compared to those of known missing individuals. If a match can be made, the remains can be identified.

There are several types of bite marks that are categorized by four degrees of impression:

hemorrhage — small bleeding spot

abrasion — undamaging mark on skin

contusion — ruptured blood vessel, bruise

laceration — punctured or torn skin

incision — neat puncture of skin

avulsion — removal of skin

artifact — bitten-off piece of body

More than just homicides, forensic odontologists may handle:

Identification of unknown human remains through dental records.

Assisting at the scene of a mass disaster.

Age estimations of both living and deceased persons.

Analysis of bite marks found on victims of attack.

ID of bite marks in other substances e.g. wood, leather and foodstuffs.

Analysis of weapon marks using the principles of bite mark analysis.

Presentation of bite and weapon mark evidence in court.

Building a picture of lifestyle and diet at an archaeological site.

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Day 31 - Serology is the study and examination of bodily fluids that is used in forensic science as a means of segregating fluids excreted by assailants or attackers in varying criminal acts. 

Modern protein mass spectrometry-based technologies make it possible to rapidly obtain a confirmatory identification of even trace quantities of human body fluids through the direct detection of fluid-specific proteins.

Currently, analysis of whole-proteome maps for six forensically relevant biological fluids: 

peripheral blood

menstrual blood

vaginal fluid

urine

saliva

seminal fluid

In terms of investigation, serology is divided into two categories:

Presumptive Testing: These tests provide two separate means of producing a result. One is to use compounds that can have an effect on blood when introduced to it. These results are a simple and quick way of proving that samples are actually blood especially if time is of the essence.

Luminol Tests

Phenolphthalein Test // Kastle Meyer Test

Acid Phosphatase Test

Prostate Specific Antigen

Phadebas Test

Confirmatory Tests: This is a more involved set of tests that are carried out using samples of what is believed to be blood and mixing them with a chemical compound that reacts adversely with hemoglobin, the resultant factor being the production of crystals under the microscope that can be identified as blood.

Takayama Test

RSID Test for Human Blood

ABAcard HemaTrace test strips

Christmas Tree Stain

RSID Test for Semen

RSID Test for Human Saliva

However, if a particular laboratory may not have a serologist on staff, their functions being performed by a criminalist, a biochemist, a forensic biologist, or other technician.

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Day 30 - Forensic chemistry encompasses organic and inorganic analysis, toxicology , arson investigation, and serology (study of blood in regards to immune system). 

Forensic chemists require a merged knowledge from the fields of chemistry, biology, material science and genetics in order to analyze all evidence that may yield chemical information. 

Additionally, a forensic chemist should become familiar with a variety of techniques and instruments including:

microscopy

optical analysis (UV, infrared, X-ray)

gas chromatography

neutron activation analysis

mass spectrophotometry

high pressure liquid chromatography

atomic absorption spectrophotometry

About 90% of forensic chemists work in labs associated with a federal, state, or local police department, medical examiner's office, forensic services lab, or branch of the Federal Bureau of Investigation (FBI).

However, those who earn degrees in forensic chemistry may also work at:

private labs

fire departments

bomb squads

the military 

other national agencies

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Day 29 - Forensic medicine, otherwise known as legal medicine or medical jurisprudence, is a branch of medicine that interprets and establishes the medical facts in civil or criminal law cases. 

The use of medical testimony in law cases predates by more than 1,000 years the first systematic presentation of the subject by the Italian Fortunatus Fidelis in 1598. Forensic medicine was recognized as a specialty early in the 19th century.

Areas of medicine that are commonly involved in forensic medicine are anatomy, pathology, and psychiatry.

Forensic medicine typically involves cases concerning:

blood relationships

mental illnesses

injuries 

death(s) resulting from violence

Forensic Medicine also provides us with clues to our ancestry with tests being carried out on Mitochondrial DNA - that strand of DNA that is passed down through the generations between bloodlines.

MtDNA is a small circular genome located in the mitochondria, which are located outside of a cell's nucleus. Most human cells contain hundreds of copies of mtDNA genomes, as opposed to two copies of the DNA that is located in the nucleus. This high copy number increases the likelihood of recovering sufficient DNA from compromised DNA samples, and for this reason, mtDNA can play an important role in missing persons investigations, mass disasters, and other forensic investigations involving samples with limited biological material.

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Day 28 - A polygraph is scientific instrument used for the detection of deception by producing recordings of physiological phenomena (breathing, galvanic skin resistance, and cardio tracing) that may be used for diagnosing truth or deception. 

The polygraph is commonly referred to as a lie detector, but it does not recognize lies. A specific physiological lie response has never been demonstrated and is unlikely to exist. Instead, it records physiological activity associated with arousal in the autonomic nervous system. Rather, the aim of the polygraph examiner is to establish a psychological set in the examinee that will increase the likelihood that any observed arousal to specific questions is the result of deceptive responses.

Several questioning techniques are commonly used in polygraph tests. The most widely used test format for subjects in criminal incident investigations is the Control Question Test (CQT). The CQT compares responses to "relevant" questions (ex. "Did you shoot your wife?"), with those of "control" questions. 

The control questions are designed for the effect of the generally threatening nature of relevant questions. Control questions concern misdeeds that are similar to those being investigated, but refer to the subject's past and are usually broad in scope; for example, "Have you ever betrayed anyone who trusted you?"

A person who is telling the truth is assumed to fear control questions more than relevant questions. This is because control questions are designed to arouse a subject's concern about their past truthfulness, while relevant questions ask about a crime they know they did not commit. A pattern of greater physiological response to relevant questions than to control questions leads to a diagnosis of "deception." Greater response to control questions leads to a judgment of non-deception. If no difference is found between relevant and control questions, the test result is considered "inconclusive."

An alternative polygraph procedure is called the Guilty Knowledge Test (GKT). A GKT involves developing a multiple-choice test with items concerning knowledge that only a guilty subject could have. However, one limitation of the GKT is that it can be used only when investigators have information that only a guilty subject would know. The interpretation of "no deception" is also a potential limitation, since it may indicate lack of knowledge rather than innocence.

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Day 27 - Forensic investigators may use stable isotopes to learn more about an individual's life history, or to narrow down a list of missing persons as a potential match for unidentified remains.

Every molecule in our bodies—including those found in hair—are made up not just of different elements, but of different ratios of stable isotopes of those elements

The stable isotope compositions of elements which are part of a substance, are a function of the origin and history of that substance. That is, two substances which are chemically the same may have different stable isotope compositions if either their origin and/or history differ.

Thus, using the relative amount of one isotope compared to another in an organism's tissues, scientists can determine important features about that organism's life.

Likewise, it is possible to identify a distinct isotopic signature by looking at multiple isotope values of a particular material. The unique combination may help to identify or differentiate between two otherwise identical materials.

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Day 26 - Otherwise known as forensic ballistics, this forensic science concerns itself with the comparison and identification of crime scene bullets and shell casing firing pin impressions with the marks on test-fired rounds in the crime lab.

The basis of firearm identification is in the microscopic individual characteristics caused during the manufacturing process. Additional imperfections may arise from use, abuse, wear, and corrosion. These imperfections caused by manufacture or over time are what make the tool surfaces in firearms unique. Firearm examiners can also analyze for distance determinations, operability of firearms, and serial number restorations.

The firearms and tool mark identification community uses a database operating system to image fired cartridge components called the NIBIN (National Integrated Ballistics Information Network) database. The NIBIN program is funded and maintained by the Bureau of Alcohol, Tobacco, Firearms, and Explosives. There are approximately 206 sites that are primarily operated by state and local crime laboratories. The allows cases to be linked together that would otherwise not be known to be related and helps detectives solve crimes.

This is due in part to the fact that firearms do not normally change much over time.  This allows for firearms recovered months or even years after a shooting to be identified as having fired a specific bullet or cartridge case.  Tests have been conducted that found that even after firing several hundred rounds through a firearm the last bullet fired could still be identified to the first.

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Day 25 - Forensic Archaeology is the specialist application of archaeological techniques to the search and recovery of evidential material from crime scenes, often but not always related to buried human remains.

The main tasks that a forensic archaeologist assists with are: 

Evidence searches 

Evidence recovery 

Evidence recording  

Scene interpretation

A forensic archaeologist’s first involvement may be to help the police locate the site where a body and victim’s personal items, or stolen goods are buried, through geological and geophysical surveying techniques, as well as using imaging and photography.

The forensic archaeologist may assist with the excavation by using similar tools and expertise to those used at an archaeological dig. This has to be done slowly and painstakingly, and the archaeologists will record and preserve anything found at every stage and depth (for example paint flakes, hair, clothing or DNA) as it may be vital evidence. 

Most sites have become incorporated into the archaeological record and require subsurface archaeological recovery techniques, such as stratigraphy or the analysis of layers of soil in accordance to their time period. 

Other general principles followed by forensic archaeologists include: 

Law of Superposition - A stratigraphic unit that underlies another must be older than the overlying unit (older is below younger layer)

Law of Inclusion - Any item (or evidence) contained within a deposit must be older than the deposit and the process by which the deposit was laid down. (ex. bricks in a wall are older than wall itself)

Law of Association - The nature of the chronological and spatial relationship between two objects within a stratigraphic unit is determined by the integrity of that stratigraphic unit. ( Items or evidence found in close proximity in the same deposit are assumed to be associated)

Law of Crosscutting Relations - Any feature that intrudes into a deposit must be younger than the deposit into which it intrudes. (ex. A grave is always younger than the soil into which it is dug)

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Day 24 - Forensic document examiners, or questioned document examiners, are forensic scientists who use a number of scientific processes and methods for examining documents—whether written, typed, or printed—related to a crime scene investigation.

The discipline of forensic document examination, often referred to as “questioned documents,” is frequently associated with white-collar crimes such as check fraud; however, in practice, this area of forensic science can be used in a wide array of cases from medical malpractice to art forgeries to homicides. This includes but is not limited to:

Authentication of documents through handwriting comparison

Comparison of typewritten and computer-generated documents

Identification of altered documents including photocopies

Determination of line sequence and indented writing

Identification of inserted and substituted material

"Reading" under whiteout or other obliterated material

Counterfeit documents and forged checks

Fraudulent wills and signature identification

Anonymous letters and synchronous writing

Medical malpractice

Forensic document examiners are extremely important especially with the availability of powerful software programs such as Adobe® Photoshop®, Acrobat® and others, as it has become significantly easier for criminals to create and manipulate all manner of fraudulent documents from contracts to currency.

Many forensic document examiners (as seen above) use only non-destructive techniques that use light and/or electrostatics to examine documents for indented impression evidence or ink differentiation. 

However, forensic document examiners should not to be confused with graphologists, who are handwriting analysis practitioners that claim to be able to discern personality characteristics based on handwriting features. Graphology is largely viewed as a pseudoscience in the eyes of the scientific community.

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Day 22 - In the early 20th century, Dr. Edmond Locard, a forensic science pioneer in France, formulated the theory which states, “Every contact leaves a trace”. This became known as Locard’s exchange principle and is the basis for all forensic science as we know it today.

Born in 1877, Dr Edmond Locard was a French criminalist renowned for being a pioneer in forensic science and criminology, often informally referred to as the “Sherlock Holmes of France”.

Known as the Locard’s exchange principle, the theory states:

“..anyone, or anything, entering a crime scene both takes something of the scene with them, and leaves something of themselves behind when they leave. In the digital world, this translates into that when two computers come in ‘contact’ with each other over a network, they exchange something with each other. This ‘something’ may show up in log files, the registry, in memory or other places on the systems.”

However, Locard never wrote down this theory in any of his notes nor did he mention the principle. Instead, he is credited with saying:

“It is impossible for a criminal to act, especially considering the intensity of a crime, without leaving traces of this presence.”

Locard is also renowned for his contribution to the improvement of dactylography, an area of study which deals with fingerprints.

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Day 21 - The full-of-foramina ethmoid and the L-shaped palatines are the only skull bones you can't feel by touching your head or face.

The ethmoid forms part of the roof of the nasal cavity, and nerves (ethmoidal cells) associated with the sense of smell that passes through tiny openings in them. Portions of the ethmoid bone also form sections of the cranial floor, eye sockets, and nasal cavity walls.

Palatines form a portion of the hard palate or the upper surface (roof) of the mouth. They make up an important part of the eye sockets and nasal cavity. The bones of the palatine also give proper shape to the orbits, nasal cavity and oral cavity.

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Day 19 - Forensic Entomology is the use of insects, and their arthropod relatives that inhabit decomposing remains to aid legal investigations.

Forensic Entomology is typically broken down into three different areas: 

Medicolegal: focuses on necrophagous or carrion insects that feast on human remains

Urban: focuses on insects that feast on both dead and living flesh, whose bites may be confused with abuse 

Stored product pests: focuses on insects that are commonly seen in food, which may indicate food contamination.

It is by collecting and studying the insects that are feeding on a body that a forensic entomologist can estimate the time elapsed since the person died. Investigators can determine this from insects by studying the development of the insect.

Forensic entomologists can also help to establish a portion of the postmortem interval (which is known as the period of insect activity, or time since colonization), assist in establishing the geographic location of death in cases of body transport, help associate the victim and suspect to each other and to the scene, and help the pathologist identify sites of trauma on the corpse. 

Additionally, entomologic evidence can be utilized as alternate toxicology samples, and their gut contents can be sources of human DNA viable for forensic testing.

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Day 18 - Environmental forensics is the application of defensible scientific methods to address questions related to release histories and sources of contamination in the environment.

Mismanagement of hazardous waste, large-scale industrial pollution, and other serious eco-crimes can now be solved through the efforts of forensic scientists. By tracing the chemical signatures of the contaminants found in the areas of incident, the individuals responsible for many ecological wrongdoings have been caught by the authorities.

Techniques such as chemical fingerprinting, chemical fate and transport modeling, hydrogeological investigation, and reconstructing operational histories, among others are at the heart of many investigations.

Environmental forensic scientists may also examine the geology and hydrology (water features and flow) of contaminated sites and surrounding areas to determine how pollutants have traveled through them, and where they came from.

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Day 17 - A decomposing body goes through four stages: autolysis, bloat, active decay, and skeletonization.

Decomposition begins four minutes after death as the heart has stopped beating and the cells are deprived of oxygen. Autolysis is the enzymatic processes in which cells break down due to the build up of carbon dioxide and waste products. 

Bloating becomes the second stage as the body may double in size due to the bacteria’s interaction with the soft tissue that creates a range of gases. A light yellow-green discoloration of the skin may also occur due to the sulfur-containing compounds. Body fluids begin to leak during this time and escape through any available orifice due to the pressure. Ruptures on the skin may occur and a strong smell is emitted, which will attract insects that will thus devour the flesh.

Active decay results when the tissue becomes liquefied and the smell is still present. 

Skeleonization has occurred once the body is fully decomposed. 

In addition to the various gases, a human decomposing body release approximately 30 chemical compounds, some with distinct odors. Common chemical compounds and their distinguishing smells include:

Cadaverine and putrescine - rotting flesh

Skatole - feces odor

Indole - mustier, mothball-like smell

Hydrogen sulfide - rotten eggs

Methanethiol - rotting cabbage

Dimethyl disulfide and trisulfide - garlic-like odor

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