Forensic Comparison Microscope in Extensive Field
Conduct DNA Analysis
Make available DNA analysis for law enforcement officers and crime laboratory if requirement needed.
Compare DNA from unsolved cases to a computerized database of DNA profiles from convicted offenders, arrestees, and other crime scene samples to provide possible investigative leads to law enforcement officers.
Examiners in the forensic biology section routinely examine items of evidence for the presence of biological material. After the proper samples for comparison purposes are obtained from forensic comparison microscope, DNA analysis can be conducted on these stains, and conclusions can be drawn as to whether an individual can be eliminated or included as a possible contributor to the genetic material identified. In cases in which a suspect has not yet been identified or an identified suspect has been eliminated, the DNA profile obtained from the evidence can be entered in the DNA Data Bank for possible matches to convicted offenders, arrestees, and or other crime scene samples
The Trace Evidence Section examines fire debris, explosives, paint, hairs, fibers, glass, gunshot residue (GSR), fracture matches, and fabric separations. In addition, the section analyzes unknown substances for identification or comparison.
Examine Physical Evidence for the Presence of Biological Material
Fire Debris
Extractions are performed and identifications are made using the gas chromatograph GC and or the gas chromatograph mass spectrometer GC/MS. Analysis is typically for the presence or absence of petroleum products although other non petroleum based accelerants may be identified.
Explosives
Analysis for explosives or explosives residues may include commercial, military or improvised explosive devices. To the extent possible, a determination of construction, ignition detonation source, and origin of materials and the function of the device is made. A variety of procedures and instrumentation may be used.
Paint
Paint, polymers, and other coatings are analyzed to ascertain probable origin. This evidence may be a vehicular as in a hit and run situation or it may be structural as in a tool being used to pry open a door. The forensic comparison microscopic examination for color, texture and layer structure is extremely important. Instrumental analysis may be performed to determine the organic and inorganic composition of the materials.
Hair and Fibers
The forensic comparison microscope is extremely important in the analysis of known and questioned hairs and fibers. Additionally, the organic composition of synthetic fibers will be analyzed using infrared spectrophotometry FTIR with a microscope accessory or pyrolysis gas chromatography PGC.
Glass
Glass analysis usually involves the comparison of the physical and/or optical properties of known and questioned glass sources. The refractive index R.I. of the glass sources is determined using the Emmons Double Variation method. If enough glass is present to reconstruct a pane, often the direction of the impact or sequence of impacts may be determined.
Gunshot Residue (GSR)
GSR analysis is performed on evidence from GSR collection kits developed and provided by the Division of Forensic Science. These kits employ sticky tape on a thumbtack like stub that is used to sample the hands of an individual suspected of firing a weapon. Examiners use an automated scanning forensic comparison microscope energy dispersive x-ray system to confirm the morphology and elemental composition of any particles found.
Fabric Separations
Microscopic analysis through forensic comparison microscope is performed on items to determine is separations in the fabric were made by cutting, tearing or normal wear. Often, test separations are made to simulate the questioned separations in an item.
General Chemical
The analysis of unknown substances for identification the forensic comparison microscope comparison purposes can be the most challenging of all examinations. Potentially every pieces of instrumentation section has available may be used to analyze a material. Examples of general chemical evidence types include, pepper sprays or maces, materials used to vandalize vehicles and adhesive tapes. If the evidence is of a type never encountered before, a method for its analysis must be developed.
