Forensic investigators use several methods when examining handwriting and documents that are suspected as being forged. In his book, Invisible Evidence, Bill O’Brien describes the way an investigation is undertaken and how authenticity is proven or disproven. Many cases of document fraud involve insurance and the misappropriation of funds.
How Handwriting is Analyzed
Handwriting analysis is a difficult science as a person’s handwriting varies from sample to sample. In some cases, an expert will be unable to reach a definite conclusion. Handwriting is examined using the following criteria:
The bigger the sample, the easier it is to make a match
Writing style, size and slope
Base line habits
Connections between letters
Construction of letters
It is possible to tell which direction a letter was written from by examining writing under a microscope. This is done by looking at the striation marks made by the ball of a ballpoint pen. There are also computer programmes that assist with assessing whether a signature is genuine or not.
Equipment used in Document Analysis
Forensic investigators have access to several machines that enable them to read a letter where the ink has been washed away, see what lies beneath scribbles and read a letter from indentations left on another sheet of paper:
An Electro Static Detection Apparatus is used to visualize indentations by applying an electrostatic charge to a transparent film. The film is laid across the page in question and once the charge has been applied, black toner is passed across the film and reveals any indentations. This method can also determine if something has been added to a journal or log after the original entry was made
A Video Spectral Comparator is used to analyze inks and see whether they are the same or different. This is done by looking at them under different lighting conditions where some wavelengths of light are blocked. This technique can uncover layers in documents where words have been scribbled out or written over
Thin Layer Chromatography is used to do a more thorough analysis of ink. The ink is mixed with chemicals and deposited onto a silicate plate where its constituents can be measured
Infrared Reflectance is used to show the residue of pencil marks. This can be done clearly even if the writing has been erased. Pencils are made of graphite which is a form of carbon – and this absorbs infrared light well
Fraud has become a sophisticated business and forensic science has kept up with it by introducing machines that can detect forgeries. Fake documents and false signatures can be exposed by modern equipment and changes to documents can be detected. Many people leave a trail of forensic evidence without realizing that they are doing so and are ultimately exposed.
Reference:
O’Brien, Bill, Invisible Evidence, David Bateman Ltd, 2007
Forensic Entomology and Flies and Maggots on a Dead Body
While other insects may be present on a corpse, flies and maggots are the main ones that are considered when investigating a homicide. This is mainly because they are the first ones to detect a dead body. In his book, Invisible Evidence, Bill O’Brien looks at the science of studying insects and what they can reveal to investigators.
Blowflies and Dead Bodies
Even in a small country such as New Zealand, there are over 50 species of blowfly although not all are attracted to a corpse. The flies settle on a dead body as it is a source of protein to feed their eggs or larvae. If a single species is present it often indicates that the corpse has been found relatively quickly. The presence of several species will point to a body that has been dead for some time.
Blowflies lay their eggs in natural orifices such as eyes, ears, nose and mouth. Other orifices will also be used if the body is naked. Gunshot or stab wounds are extremely attractive to flies. It is common for flies to only lay eggs during sunlight hours.
What does an Entomologist do when Examining the Body
When a body is found, an entomologist will take samples of eggs and larvae and rear these in a laboratory to determine the species and age at which they were found. Some maggots prefer a wet environment and others are carnivorous. Each species will be reared in isolation and may be fed cat food. Investigators will also note the weather conditions and environment in the area where the body was found. The surrounds will be searched for signs of further insect activity.
What can Forensic Entomologists Determine from Insects on a Corpse
Maggots go through three stages of growth which are roughly as follows:
•The first stage begins when an egg hatches, and lasts for 24 hours
•The second stage is the period of active growth and feeding and lasts two to five days depending on the species and the temperature
•The third stage involves moulting and the maggot moves away from the food source to pupate. For this reason, samples are taken of plants and soil around a body as the maggots may burrow down into the ground
Live specimens are taken to the laboratory and half are killed by immersion in near-boiling water; the others are reared to maturity. The dead larvae are measured and examined to determine their age. When the live specimens mature, a positive identification is made of the species. Armed with this information along with the weather conditions, the amount of sun the body was exposed to and other factors, an entomologist can give an estimated time of death. The accuracy may be out by a couple of days or in the case of a badly decomposed body, a couple of weeks. Even so, a forensic entomologist can provide invaluable information to a homicide investigation.
Flies and maggots are the most common insects to be found on and around a dead body. They often arrive within minutes of death and lay eggs and larvae that feed off the protein in the corpse. Forensic entomologists rear maggots from a crime scene and by doing so, are able to give an approximate time of death.
Reference:
O’Brien, Bill, Invisible Evidence, David Bateman Ltd, 2007
Blowflies and Dead Bodies
Even in a small country such as New Zealand, there are over 50 species of blowfly although not all are attracted to a corpse. The flies settle on a dead body as it is a source of protein to feed their eggs or larvae. If a single species is present it often indicates that the corpse has been found relatively quickly. The presence of several species will point to a body that has been dead for some time.
Blowflies lay their eggs in natural orifices such as eyes, ears, nose and mouth. Other orifices will also be used if the body is naked. Gunshot or stab wounds are extremely attractive to flies. It is common for flies to only lay eggs during sunlight hours.
What does an Entomologist do when Examining the Body
When a body is found, an entomologist will take samples of eggs and larvae and rear these in a laboratory to determine the species and age at which they were found. Some maggots prefer a wet environment and others are carnivorous. Each species will be reared in isolation and may be fed cat food. Investigators will also note the weather conditions and environment in the area where the body was found. The surrounds will be searched for signs of further insect activity.
What can Forensic Entomologists Determine from Insects on a Corpse
Maggots go through three stages of growth which are roughly as follows:
•The first stage begins when an egg hatches, and lasts for 24 hours
•The second stage is the period of active growth and feeding and lasts two to five days depending on the species and the temperature
•The third stage involves moulting and the maggot moves away from the food source to pupate. For this reason, samples are taken of plants and soil around a body as the maggots may burrow down into the ground
Live specimens are taken to the laboratory and half are killed by immersion in near-boiling water; the others are reared to maturity. The dead larvae are measured and examined to determine their age. When the live specimens mature, a positive identification is made of the species. Armed with this information along with the weather conditions, the amount of sun the body was exposed to and other factors, an entomologist can give an estimated time of death. The accuracy may be out by a couple of days or in the case of a badly decomposed body, a couple of weeks. Even so, a forensic entomologist can provide invaluable information to a homicide investigation.
Flies and maggots are the most common insects to be found on and around a dead body. They often arrive within minutes of death and lay eggs and larvae that feed off the protein in the corpse. Forensic entomologists rear maggots from a crime scene and by doing so, are able to give an approximate time of death.
Reference:
O’Brien, Bill, Invisible Evidence, David Bateman Ltd, 2007
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