Physical Evidence One of the main types of physical evidence is that of our fingerprints. We carry around our own unique maps of swirls and ridges on our fingertips, thus enabling judges and juries to use fingerprints in deciding our innocence and guilt in a court of law (Sealey, 2016). Fingerprints are the most incriminating type of evidence that can be used in a criminal case. Fingerprints are one of the most reliable forms of identification, because no two people have the same fingerprint pattern, thus making fingerprints irrefutable in courtrooms for decades now. This makes fingerprints the most fundamental tool for an accurate and precise identification of criminals (Criminal Justice Degrees, 2016). Fingerprints consist of: friction
…show more content…
DNA evidence can be found on hats, bandanna, eyeglasses, tissue, bottle, blanket, tape, bite mark, used condom, and a fingernail. Law enforcement takes extra precautions to work lab personnel or lab techs to ensure that the DNA evidence is not contaminated. This involves but is not limited to wearing gloves, using disposable instruments that can be disposed of after each sample is taken. When investigators find a piece of evidence they place it in a paper bag or envelope, not plastic. The officers or techs then label the bags with information about the evidence enclosed, where it was found, and where it will be transported to. As per the chain of custody, this has to be followed every time the evidence is moved or examined. Most labs use restriction fragment length polymorphism or RFLP to analyze DNA.RFLP requires investigators to dissolve the DNA in an enzyme that breaks the strand at specific points. The number of repeats affects the length of each resulting strand of DNA; investigators can then compare samples by comparing the lengths of the strands. Once the DNA in question has been amplified a short tandem repeat (STR) analysis is performed to determine the base pairs that are in repeat. This is to provide the most accurate DNA sample. The FBI has chosen 13 STR loci to serve as the standard of DNA analysis, so the probability that two individuals have the same results is 1 in 1 billion or greater (Harris,
DNA evidence can be found on hats, bandanna, eyeglasses, tissue, bottle, blanket, tape, bite mark, used condom, and a fingernail. Law enforcement takes extra precautions to work lab personnel or lab techs to ensure that the DNA evidence is not contaminated. This involves but is not limited to wearing gloves, using disposable instruments that can be disposed of after each sample is taken. When investigators find a piece of evidence they place it in a paper bag or envelope, not plastic. The officers or techs then label the bags with information about the evidence enclosed, where it was found, and where it will be transported to. As per the chain of custody, this has to be followed every time the evidence is moved or examined. Most labs use restriction fragment length polymorphism or RFLP to analyze DNA.RFLP requires investigators to dissolve the DNA in an enzyme that breaks the strand at specific points. The number of repeats affects the length of each resulting strand of DNA; investigators can then compare samples by comparing the lengths of the strands. Once the DNA in question has been amplified a short tandem repeat (STR) analysis is performed to determine the base pairs that are in repeat. This is to provide the most accurate DNA sample. The FBI has chosen 13 STR loci to serve as the standard of DNA analysis, so the probability that two individuals have the same results is 1 in 1 billion or greater (Harris,