Investigations and Principles

Investigations and Principles

Franklin 1

Jonathan Franklin

Allen Layne

Criminal Investigations


Investigations And The Principles

A successful crime scene investigation depends deeply on the collection and analysis of various kinds of evidence. Forensic scientists rely on the classification of certain evidence and they have different ways of dealing with it. One major difference is biological and physical. Physical evidence refers to the collection of anything at the crime scene that comes from a nonliving origin. Where biological evidence refers to anything from a living being. The most important can be anything from fingerprints, marks on surfaces, bullet casings, and bullets. Biological evidence includes bloodstains and DNA.

Locards Exchange Principle says that when two objects come into contact with each other then one part of one object is left on the other. This deems items as physical evidence and biological. Some evidence is found in minute quantities known as trace evidence. Something that is essential for trace evidence is fibers, which is usually found on clothing or furniture. Trace evidence is invisible to the naked eye and is collected by either brushing or vacuuming the area of the crime scene.

Homicide cases and physical evidence go hand in hand with one another. Without evidence you are risking a loss of your case. IOWA CITY, Iowa - In the hours and days following John Versypt’s shooting death in south Iowa City, officers processed the crime scene and sent numerous pieces of evidence to the state lab for testing. As the hours went on all leads reach their end. There wasn’t any footprints at the scene no fingerprints on the railing, according to testimony in Justin Marshall’s first degree murder trial.

A revolver found at the scene and five shell casing were found and ran for fingerprints but nothing turned up.

Hours after the fatal shooting in Oct. of 2009, officers canvassed the area and found nothing of significance....

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