Scanning Electron Microscopes are predominantly being used during forensic investigation of a certain incident in order to establish the details of such event and the persons and things involved. How it has evolved is due to the fact that forensic examination of substances found at a crime scene can often establish the presence of the suspect at the scene. One of the oldest techniques of forensic science is dusting the scene of a crime for fingerprints, impressions of the fingertips left on surfaces touched bare-handed. In one technique of obtaining a fingerprint, a technician spreads fine powder over a surface with a brush or magnetic wand. The powder bonds to proteins secreted by the sweat glands on the skin ridges of the fingertips. As soon as the excess powder is removed, an outline of the contours of the ridges stays. In other techniques, the print can be chemically treated to expose the forms. For the reason that no two fingerprints are the same, fingerprinting offers a positive means of identification. Using the scanner electron microscope and computer technology law-enforcement officers can easily record fingerprints digitally and to communicate and obtain fingerprint information electronically for rapid identification.

Other proof present at a crime scene may include skin, hair, blood, or semen. A breakthrough in technology permits scientists to study the deoxyribonucleic acid (DNA), or genetic material, of these substances to ascertain whether they belong to the victim or to a suspected assailant. As a result of a high-technology method known as the polymerase chain reaction (PCR), a laboratory can quickly clone, or multiply, the DNA from a tiny sample of any of these substances. This procedure generates enough DNA to compare with a sample of DNA taken from a suspected criminal. The use of DNA for such identification purposes is commonly referred to as DNA fingerprinting. With the use of the scanning electron microscope these things can readily be determined.

Human bite marks can also serve as circumstantial evidence. Such bites may be found upon the body of a homicide victim or within pieces of food or other objects, such as chewing gum, found at the crime scene. A forensic scientist can fill the impressions caused by these bites with liquid plastic. Upon hardening, the cast formed is an extremely accurate replica of the assailant’s teeth, which can be compared with a cast made from the teeth of the suspect.

District attorneys routinely call upon medical examiners to give expert testimony in a trial, especially concerning the findings of an autopsy and the results of laboratory tests. Expert testimony is that given by a specialist who has been recognized by the court as having expert knowledge about evidence in the case. Such testimony is governed by different rules than the testimony of ordinary witnesses in a trial. Ordinary testimony is restricted to statements concerning what the witness actually saw or heard. An ordinary witness is prohibited from stating opinions about the case and from quoting statements made by other people. In contrast, an expert witness is allowed to express an opinion about the validity of the evidence in a case and may quote the statements of other experts in support of an opinion.

In order to fast track the investigation and other tedious, long-straining methods of resolving crimes and obscure incidents as well as verification of DNA of persons, bite marks, and fingerprints among others, the scanning electron microscopes are being utilized. This instrument has been such a great helped for the investigators and other forensic experts.