Crime Scene Investigation Case Study

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| Crime Scene Investigation | Case Study #1 | | | 1/26/2013 | OBTAINING and RECORDING PHYSICAL EVIDENCE When it comes to identifying people that have committed a criminal act, the most positive means is through fingerprints. When we are born, our fingerprints stay with us until we die and our bodies start decomposing. To the human eye our fingerprints look the same, however, further investigation will show that each of us have a unique set of friction ridges that comprise our fingerprints and sets our identity apart from each other. At a crime scene, there are two different types of fingerprints that may be found. Patent prints are visible to the human eye. Latent prints are “unintentional prints found on items of…show more content…
When the bi-chromatic powder is used on dark surfaces it will look light and it will show up dark on light surfaces. The best rule for processing latent prints using powder is to use less lifting powder than you think you are going to need. Many latent prints can be ruined by over processing with powder. David suggests “give the print powder jar a quick shake before opening the lid” then goes on to say “remove the lid and place the fingerprint brush inside the lid” (Spraggs, 2007). The lid will retain enough powder to start processing the latent print. A precise amount of pressure applied while spinning the brush will produce a good print with good ridge detail. He mentions that too much powder will fill the ridges and over process the print and too little will not produce enough, keeping in mind that too much contact between the brush and the print will damage the print. Once the print has been developed it is time to begin lifting the print. Lifting tape comes in a variety of widths and compositions. General lifting tape is used on flat surfaces and polyethylene tape is great for curved surfaces like door knobs. An important key in applying the tape is to keep it evenly and as smooth as possible. David suggests using a credit card to
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