How DNA Typing Has Changed Forensic Science

DNA typing was first used in Great Britain for law enforcement purposes in the mid- 1980s. It wasn't employed in the United States until 1987. DNA profiling has changed forensic science. DNA technology has given police and the courts a means of identifying the suspects of rapes and murders. Today, the Federal Bureau of Investigation performs the bulk of the forensic DNA typing for local and state law enforcement agencies. In criminal investigations, DNA from samples of hair, bodily fluids or skin at a crime scene is compared with those obtained from suspected suspects. DNA typing and PCR by court systems around the united states has led many places to pass laws requiring people convicted of sex offenses and other crimes to be DNA typed and
included in statewide offender databases. DNA typing has had a positive return in many states. In most cases the genetic records of men in the penitentiary were matched with samples recovered from a sexual assault. It has also exonerated individuals of crimes for which they had been convicted before DNA fingerprinting was put into use. http://faculty.ncwc.edu/toconnor/425/425lect15.htm http://www.forensica.com/criminal-dna-testing.htm

In the early part of the nineteenth century firearm and tool mark identification was recognized by numerous judicial systems in several countries all over the world.
In the United States, the Scientific Crime Detection Laboratory began operations at Northwestern University in late 1929 or early 1930, followed by formation of the Federal Bureau of Identification Laboratory in 1932. Additionally, many other countries also recognized the requirement to provide this type of forensic analysis and established firearm and tool mark sections either in existing laboratories or as new laboratories. Over the next few years, several laboratories were established. In 1960 the misuse of firearms in criminal cases increased. People wanted to continue research so thirty-six individuals met in Chicago, in February 1969, and organized the Association of Firearm and Tool mark Examiners. Many examiners continue to research and experiment the various aspects of the field. The advances include innovations in one of the primary tools of the firearm and tool mark examiner — the binocular comparison microscopes. Many of the current comparison microscopes have been equipped with photomicrography and closed circuit television units, which allow for direct viewing or instant digital
documentation. http://www.firearmsid.com/new_index.htm http://www-medlib.med.utah.edu/WebPath/TUTORIAL/GUNS/GUNINTRO.html

http://faculty.ncwc.edu/toconnor/425/425lect06.htm

Luminol is a chemical that glows greenish-blue when it comes into contact with blood — even traces that are years old. To be exact, it reacts to hemoglobin, an oxygen-carrying protein in red-blood cells. Luminol is generally applied with a sweeping motion from a spray bottle or pump sprayer. Luminol is very sensitive and commonly used to locate very faint blood where attempts have been made to clean suspected areas. Invisible footwear patterns can be uncovered at a crime scene when misted with Luminol. Officers then photograph or videotape the result, using a flash technique that picks up the glow while making the area around it visible and identifiable on film, so the context of the crime scene isn't lost. Even though there is a glow dose not mean there's blood present. Luminol reacts to some metals, paints, cleaning products and plant matter. http://people.howstuffworks.com/luminol3.htm http://www.bvda.com/EN/sect6/en_6_1a.html http://www.centralhigh.net/~wcrawford/Timeline.html