Forensic Microscopes

Study a Crime Scene of Your Own using a Forensic Microscope

forensicmicroscopes — Sat, 19 May 2007 10:15:03 +0000

See how several clues you can recognize in your own crime scene. Choose a room (e.g., kitchen, living room, and bedroom) or division of a room and go over it cautiously, discovering any trace evidence such as hair, clothing fibers, and chips of paint. You be able to gather these with a pair of tweezers and put them in envelopes or Ziplock bags to discover later. Are there several prints or scuff marks on the floor from shoes? Or there are bits of soil or rock that may have been tracked in? To be detailed, record all of these clues plus create sketches in an investigation notebook. (more…)

Physical Evidences

forensicmicroscopes — Sat, 19 May 2007 10:13:54 +0000

When the physical markings of a fired bullet recovered from a crime scene are too mutilated for visual comparison under the microscope or the firearm used in the crime is not recovered, the bullet can be compared with other bullets associated with a suspect by its elemental composition. When a crime scene bullet contains the same analytical elemental concentrations or match in composition, as the bullets from known cartridges, a single source for these bullets cannot be excluded. During the manufacturing processes, thousands of lead specimens like bullets and bullet cores are produced with analytically indistinguishable compositions. However, those lead specimens that share the same composition are generally packaged within the same box of cartridges, or in boxes of cartridges of the same caliber and type at the same manufacturing plant, on or about the same date. When the differences in element concentrations are small but analytically significant, a comparative examination can be used to differentiate among bullets made of different alloys or to exclude a single source for bullets of the same alloy. (more…)

Microscope and Macroscope

forensicmicroscopes — Sat, 19 May 2007 10:08:15 +0000

Certain Crime Laboratory Division affords twenty four hours assistance to local law enforcement agencies in processing illegal and extremely hazardous clandestine laboratories. This includes help in dismantling the laboratory, recognizing hazardous fumes and chemicals, and handling, preserving, and packaging evidence. Powder from evidences is examined in the laboratory under the microscope for crime scene evidences processing. Bullets collected for comparison to a specific firearm are examined first to see if they are of a caliber that could have been fired from the submitted firearm. They are then examined to determine if the pattern of rifling impressions found on the bullet match the pattern of rifling contained in the barrel of the questioned firearm. If these class characteristics agree the next step is to try to make a positive match between the individual characteristics that may have transferred to the bullet from the barrel. (more…)

Crime Laboratories

forensicmicroscopes — Sat, 19 May 2007 10:04:48 +0000

Crime laboratories play a vital role in the criminal justice process. Scientific testimony is often the deciding factor in the judicial resolution of civil and criminal cases. The results of scientific analysis of evidence in the blood, semen, shreds of clothing, hair, fibers, glass, paint, soil, bullets or bullet casings, impressions, and other physical indications left at the scene of a crime can seem more compelling to a jury than the testimony of eyewitnesses. The timely scientific analysis of any physical evidence relating to crimes against the citizens of the state is an integral part of the laboratory services. To support demands, forensic laboratory services are grouped into specialties, which include the analysis of different types of evidence. Body fluids like blood, saliva, semen, vaginal samples, and stains are examined and analyzed. Their identification and characterization can implicate or eliminate a suspect. The information derived from the examinations assists investigators as they reconstruct the events that occur during crimes, especially crimes against persons. (more…)

Microscopy and Spectroscopy

forensicmicroscopes — Sat, 19 May 2007 10:02:50 +0000

The cause and manner of a death are not always evident, even after visual examination and dissection and examination under the microscope. From 1800 onward, scientific investigators continually devised procedures and instruments, technologies of visibility to reveal what the naked eye could not see. Chemical analysis helped detect traces of poison in the victims body. Microscopes made it possible to see tiny lesions, crystals, and hairs. Spectroscopic analysis of blood and other materials helped match trace elements linking victim and killer. As commercially manufactured poisons became increasingly available in the 19th century, poisoning became known as a modern and disturbingly hard to detect method of killing. In response, researchers developed toxicology as a specialized field of forensic medicine, and devised specific tests for poison, most famously the 1836 Marsh Test for arsenic. The new science of toxicology was plagued by difficulties. In the courtroom and laboratory, seemingly reliable tests were shown to be flawed. (more…)

Laboratory techniques

forensicmicroscopes — Sat, 19 May 2007 09:57:04 +0000

Forensic science uses sophisticated laboratory techniques with the use of thr microscope to detect the presence of substances in the victim, in the suspected criminal, or at the crime scene. For example, in determining whether alcohol was involved in a crime, the amount of alcohol in the blood can be measured in two ways. One is to measure the amount of alcohol exhaled in the breath of an individual, which reveals the concentration of alcohol in the persons blood. Recent advances in technology have produced alcohol breath testing instruments so accurate that their results are evidential, capable of providing evidence in court. Blood alcohol level can also be determined by actual blood tests, usually through gas chromatography. In this method, the blood sample is vaporized by high temperature, and the gas is then sent through a column that separates the various chemical compounds present in the blood. (more…)

Hair Identification using the forensic microscope Part II

forensicmicroscopes — Sat, 19 May 2007 09:55:46 +0000

Hair Identification using the forensic microscope Animal Versus Human Hairs Human hairs are discernible from hairs of other mammals. Animal hairs are categorized into the following three basic types. 1. Guard hairs that outline the outer coat of an animal and give protection 2. Fur or wool hairs that shape the inner coat of an animal and offer insulation 3. Tactile hairs (whiskers) that are seen on the head of animals give sensory functions Some types of hairs found on animals consist of tail hair and mane hair (horse). Human hair is not so distinguished and may be described as a modified combination of the characteristics of guard hairs as well as fur hairs. (more…)

Forensic Science & Archeology History

forensicmicroscopes — Sat, 19 May 2007 09:54:44 +0000

Forensic Science & Archeology History Forensic scientists dont just work at crime investigations. They take part in a main role in understanding anthropological and archaeological discoveries, like the so called ice people and bog people ancient bodies found any frozen or preserved in bogs. Together bogs and ice stop bacteria growth that would decompose bodies. Bogs also have acids that tan a bodys skin like leather. Presently the one time these naturally mummified bodies are establish, scientists study them for clues to their past. Did they die violent deaths? What did they eat? What did they do for a living? Forensics can assist response these questions, though at times the evidence is not enough to make conclusive judgments. (more…)

Information About Forensics

forensicmicroscopes — Sat, 19 May 2007 09:53:12 +0000

Information About Forensics Crime scene investigation has developed ever since Sherlock Holmes day, though cautious examination of facts is just as significant nowadays. The science that deals with crime investigation, or science that is applied to law cases, is named forensic science. Modern techniques for working out forensic cases started to grow in the late 19th century. In the 1890s Francis Dalton summed up previous studies in a book concerning fingerprints, signifying that each person has exclusive prints that do not change with age. At the similar time, Argentina turned out to be the first country to use fingerprinting in criminal cases. In 1904 the New York City police force started gathering the fingerprints of prisoners. (more…)

Fiber Evidence, Assigning Significance

forensicmicroscopes — Sat, 19 May 2007 09:51:46 +0000

Whenever a fiber found on the clothing of a victim matches in the laboratory through comparison of samples under the microscope, the known fibers of a suspects clothing, it can be a significant event. Matching dyed synthetic fibers or dyed natural fibers can be very meaningful, whereas the matching of common fibers such as white cotton or blue denim cotton would be less significant. In some situations, however, the presence of white cotton or blue denim cotton may still have some meaning in resolving the truth of an issue. The discovery of cross transfers and multiple fiber transfers between the suspects clothing and the victims clothing dramatically increases the likelihood that these two individuals had physical contact. When a fiber examiner matches a questioned fiber to a known item of clothing, there are only two possible explanations, like the fiber actually originated from the item or clothing or the fiber did not originate from the item of clothing. (more…)