Types of Forensic Examinations

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Technological advances have revolutionized the methods used in forensic examinations. Lab equipment forensic examiners utilize, can run analysis from a sample taken from the evidence. Special software, tools, and computers have made the process of identifying important pieces in crime scene simpler than ever before. Examples of these useful equipment forensics use are Alternative light photography, video spectral comparator 2000, 3D facial reconstruction software, Automated fingerprint identification systems, Link analysis software used specifically by forensic accountants, atomic absorption spectrophotometer, and gas chromatography tools.

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Alternate Light Photography

Light sources that can be seen by naked eye were used during most crime scene investigations in the past. Forensic investigators would rarely resort to the use of ultraviolet (UV black light) but white light remained the main light used in these investigations. In the 1970’s, the Royal Canadian Mounted Police helped develop the use of argon-ion lasers. Since they were expensive, complex, slow, and bulky machines they were impractical for use during the crime scene, so it remained useful in the crime laboratory.

Later in the 1990s, wide access of high incandescent lamps gradually transformed alternate light source analysis.

Examining physical evidence became easier since these machines weighed less than 20 pounds, provided an intense light beam that could penetrate through various filters including visible blue, green, yellow, and red light. Using these color filters increased the ability to reveal a wide range of evidence that would have remained undiscovered. For example, a combination of blue and orange filters allows the examiner to see whether bruising has occurred below the skin.

Despite its ability, alternate light requires certain materials to have a property called fluorescence. “Fluorescence occurs when light of a certain color and light frequently strikes an object and the object returns lights of a different color and frequency.” (Penven, 2013)

Taking this into account the technician at the crime scene is required to use the filters in order to block the unwanted visible light and pass the fluorescence. UV light does not require the filters, but eye protection is needed, preferably goggles. Considering the use of alternate light sources in crime scene investigations, UV light is used to intensify the bruises or bite marks to make them noticeable and search for more trace evidence. Infrared photography magnifies difficult to see blood on similar dark colors or patterned clothing and tattoos post mortem difficult to see due to outside environmental factors affecting it. Bodily fluids such as urine and saliva can be identified through their natural fluorescent properties using the UV light. The creation of Light Emitting Diodes (LEDs) has increasingly advanced evidence recovery 1- and 3-watt LED’s can be installed in small handheld flashlight and their performance is remarkable. (Penven, 2013) (Richards, 2016)

Video Spectral Comparator 2000

Another important instrument to forensic crime scene evidence gathering is the Video Spectral Comparator 2000 (VSC 2000). The imaging device, VSC2000, allows the document analyzer to examine inks, visualize hidden security features in papers such as driving licenses and passports, and even reveal other alterations in a document. The two main components of the VSC200 is a desktop computer and an imaging device. The desktop computer’s features include manufacturer provided software, standard size monitor and a readable and writable CD-ROM for storing the bitmap image files.

A color charge device video camera, a black and white CCD video camera, barrier filters, and many radiant energy sources are included in the imaging device. Although using variable light sources in running document examination was not a new concept in the early 2000’s, the VSC2000 made the process simpler and faster. At the touch of a button, the machine can allow the user to select combinations of light and filter techniques to capture necessary images. Compared to earlier versions, the VSC2000 comes with improved filters and light sources and complete computer-based operations. (Mokrzycki, 1999)

3D Facial Reconstruction

In forensics, certain techniques might fail in aiding identification of human remains, however, there is an alternative, the 3D facial reconstruction method. Traditional methods of identification such as dental records, DNA analysis etc. are avoided if from conditions of the remains result in nothing being able to be recovered or little to no evidence. Because of advancements in 3D technology, a computer that is efficiently fast and cost effective assisted in the development of the forensic facial reconstruction technique. The reconstruction of the facial region is ultimately a useful tool to forensic science for it not only helps with facial recognition but also leads to positive identification of the remains.

Behind forensic facial reconstruction is artistic skill and scientific methods. It can reconstruct the skull with computer generated soft tissue in order to retrieve the image of the person whose remains are being examined for their identification. Reconstruction techniques are analyzed and carried out using computerized software. Past methods of manual facial reconstruction influenced the software used for digitalized facial reconstruction. 3D animation software such as Free Form Modelling PlusTM, Wilmington MA, and Sensable Technologies could be used in computerized systems to replicate the face on top of the skull.

Systems such as, Phantom Desktop Haptic device, use a virtual sculpture software and haptic feedback tools. The purpose of the haptic feedback in these systems is to provide crucial skeletal details the examiner cannot determine including the strength of the muscle attachment eye position, malar tubercle placement, etc. During analysis, this feedback system can sense the curves and pits of the skull. Multiple images of the same model are created faster and skillfully using this system displaying its benefits of practicality and overall efficiency in forensic science. (Gupta, 2015)

Automated Fingerprint Identification System (AFIS)

In crime scenes, the collection of evidence requires careful observation of the area. Sometimes evidence left behind in the scenes are not enough to help identify the culprit. Not surprisingly, fingerprints collected off the scene or an individual's remains are frequently successful in connecting the offender to the crime. Because finger prints are unique, misidentifying a person from a successful fingerprint withdrawal is rare. Automated finger print analysis (AFIS) is a reliable asset to forensic science because of how accurate and quick it manages to identify the owner of the fingerprint.

Automated Fingerprint systems are reliant on a latent print examiner that left prints of any surface they might be found on at a crime scene. Once an identification is made, the background of the individual is collected and reviewed. There are four major components that make the automated finger analysis system superior in evidence processing and identification. First, there is no need for an actual print classifier because of the automated process. Instead of matching fingerprint file to another manually, the automation simplifies the work load carried out. Secondly, fingerprint images that are collected from the individual by hand or by scanners are stored in the database that is searched thoroughly. Third, the persons’ fingerprints are compared on the database with other filed fingerprint images locally, statewide, and nationwide. This is known as the identification part of the automated fingerprint system.

Last of all. The automated fingerprint identification system is considered a system for its use of software and computer. With those it can and is capable of interacting with other systems used for identification like other automated fingerprint identification systems. The way automated fingerprint identification systems link one fingerprint pattern to another is by pin pointing certain characteristics of the print. The automated fingerprint identification system coverts the points near the ridges, splits, the directions of the ridges, and light areas that are captured in an image the in turn brings up the closest match from the search database.

The part of the automated fingerprint identification system that takes the displayed characteristics from the print image are called automated identification system coders. One of the largest automated fingerprint identification systems that is in the United States of America and operated by the Criminal Justice Information Services section part of the FBI. The Automated Fingerprint Identification System is a valuable tool outside of forensic science such as in the military for applications and the government. (Moses, 2011)

Link Analysis Software

Thanks to link analysis software and its tools, global terrorists can be captured along with their money and their accomplices that are identifies by the experts who inspect the computer records such as from banks, airlines, company transactions, charities and so on. Forensic accountants stationed in private industry in order to take down embezzlement and frauds, have since used link analysis software to do so. Accounting, inspecting, and investigating are included in the type of skill that a forensic accountant has in order to analyze documents and financial records that are used as evidence in trial of the accused.

The benefit of link analysis software includes forensic accountants piecing together million and millions of information together to then study it and understand the case that is forming. The most common link analysis tools are the following: NetMap Analytics Incorporate's and i2 Inc.’s Analysts notebook. Link analysis software incorporates visuals to help with the information gathering and dissection. Its tools create colored lines or thickened lines in charts to display connections between the transactions of people or companies. The activity in within specific fountains, like bank accounts, that is out of the ordinary, is tracked by the link analysis software. Irregular patterns are noted and brought to view by the software. Every transaction is carefully looked at by the software making it easier to observer and interpret the normal or suspicious behavior.

Though irregular actions do not imply suspicious behavior, the link analysis software does a good job in avoiding these types of occurrences. Only actual suspicious behavior is flagged by the software that would have been otherwise gone unnoticed. With those helpful visuals it makes it easier to comprehend the transactions being processed. Link analysis software is incredibly fast, analyzing several boxes of documents in fifteen minutes while two examiners took days to complete the task. It makes work easier by including potential lawbreakers and their illicit activities. The evidence gathered that successfully locks away a criminal is investigated by forensic accountants with access to link analysis software. (Chadrow, 2002)

Atomic Absorption Spectrophotometer

The atomic absorption spectrophotometer is an instrument used to identify the trace evidence of metals involved. For example, if around the crime scene there is gunshot residue, the spectrophotometer can measure the quantity of lead, copper, barium, and antimony left. Mercury, a heavy metal poison, can be recognized by the atomic absorption spectrophotometer as well as other types. The atomic absorption spectrophotometer is designed with a flame burner to reduce the sample to separate atoms.

Another type of design in atomic absorption spectrophotometer is instead of a flame burner there is a graphite furnace. It is also used for heating and breaking the metal into small particles. The instrument, atomic absorption spectrophotometer, is designed for the analysis of single metals or chemical elements in the sample. When the sample is first being prepared for the analysis by the atomic absorption spectrophotometer it is dissolved in an acidic solution. Then the sample, now dissolved, is put in the flame burner supplied with an acetylene (gives off a pure white light) and nitrous oxide combination along with air. Once in the flame, the chemicals evaporate resulting in free metal atoms because the chemical bonds are broken off.

Because of this process, atoms are then able to absorb electromagnetic radiation. Each element has a specific and different wavelength absorption. Another component of the atomic absorption spectrophotometer is the hollow cathode lamp. At a specific wavelength, the lamp directs a beam of light towards the flame and the metal. The amount of light then absorbed by the metal is the same to as the quantity of the metal there. Afterwards, the light passed through the monochromator that filters out light wavelengths not needed any longer. This allows the wavelength that will be analyzed to reach the detector without confusion. In the detector, the amount of light the metal absorbed is measured.

If a sample that contains more concentration of the specific metal with absorb more light. If no light is absorbed and detected, that means that the sample had little amounts in it. The only downside to atomic absorption spectroscopy is that it needs a separate lamp for each type of metal analyzed. In order to properly analyze the metal in hand, the forensic scientist knowledge of metals is crucial. They must select the right lamp based on the element they have sampled before they start the process. (Bell, 2008)

Gas Chromatography

The examination of drugs and other related substances by the forensic examiner is frequently done using gas chromatography. Many instruments are needed in the lab to identify the substances. The gas chromatography tool helps in forensic drug sample analysis providing additional information on the substance. The gas chromatography instruments can analyze the complex components and mixtures the drug contains as well as other compounds. Synthetic substances can also be read by using gas chromatography. Gas chromatography measures the things included in the substance or drug.

There is a separation tube in the chromatography machine called the column. The column is where the sample solution goes to after being injected into chromatography instrument and then enters a stream of gas. All the different materials are divided inside the column and the gas chromatography detector measures the amounts as they exit the separation tube. When the concentration of a sample is not known, then a sample with a concentration that is known is injected into the chromatography machine. (Shipman, 2013)

In conclusion, forensic examinations rely on technology such as these examples and many others. Analysis of crime scene samples are done easier and faster with machines and its software. With these reliable technology tools, forensic information gathering, and inspections are more successful in getting accurate results for a case.