DNA Lady
Forensic DNA Evidence
Recent advancements in DNA Technology are enabling law enforcement officers to solve cases previously thought to be unsolvable. Today, law enforcement with a knowledge of how to identify, preserve and collect DNA evidence properly can solve cases in ways previously only seen on TV. Much the way Trekkies envision a futuristic world of beaming molecules from one surface to another - law enforcement envisions the use of DNA evidence solving crimes faster, more reliably and more frequently than heretofore methods of fingerprinting, eye witness and the old fashioned "gum-shoe" work ethic of eras gone by.
Because of the uniqueness of each person's DNA, evidence collected at a crime scene can either link a suspect to a crime or eliminate a suspect. Further, whether blood, saliva or skins cells are collected - a person's DNA is the same throughout. DNA evidence can also identify a victim or suspect through samples obtained from relatives even when no body can be found. Crimes scenes can be compared across a State or Country and the same perpetrator identified if his/her DNA is present.
Forensically valuable DNA samples can be found on evidence that is decades old. However, several factors can degrade the viability of the sample including but not limited to heat, sunlight, moisture, bacteria or mold. DNA is found is blood, semen, skin cells, tissue, organs, muscle, brain cells, bone, teeth, hair, saliva, mucus, perspiration, fingernails, urine and feces - although most labs are loath to be testing feces looking for viable DNA samples and some of the private labs have discontinued offering such services.
Creative crime scene investigators can collect DNA evidence from non-traditional sources, such as saliva on cigarette butts or soda cans, sweat on baseball bats or a similar weapon, sweat inside a hat, bandanna or mask discarded at a crime scene, bite mark's containing saliva from the perpetrator, scrapings from underneath a fingernail (this we have all seen on TV shows like Law & Order or CSI). Today's crime scene detective has to visualize the crime and discern where and when DNA samples were transferred during the commission of a crime from perpetrator to victim; from perpetrator to scene surface etc., DNA profiles of those involved in the crime scene investigation (other than the perpetrator and/or victim) should be provided to the lab in order to eliminate possible contamination to evidence.
DNA collectors, laboratory personnel, lawyers and investigators should work as a cohesive unit to determine the most probative pieces of evidence and to establish priorities. Most state DNA laboratories are backlogged with evidence yet to be analyzed; however, there are many accredited and reliable private DNA laboratories that can be utilized in DNA detection and profiling.
Since biological material (DNA evidence) may contain hazardous pathogens such as HIV or Hepatitis B or the most recent H1B1 flu, care must be taken when collecting and/or handling samples. Given the nature of DNA evidence, officers should always contact a local DNA expert for answers about evidence collection.
Every State in the Nation has or is implementing a DNA index of individuals convicted of certain crimes - usually felonies (BARRMS + K - thanks to my college Criminal Justice professor). Upon conviction, the DNA sample is analysed and profiled and entered into a DNA Database. Just as fingerprints found at a crime scene can be run through AFIS (Automated Fingerprint Identification System) in search of a suspect or link to another crime scene, DNA profiles from a crime scene can be entered into CODIS enabling law enforcement officers to identify possible suspects when no suspect or lead existed.
Recent advancements in DNA Technology are enabling law enforcement officers to solve cases previously thought to be unsolvable. Today, law enforcement with a knowledge of how to identify, preserve and collect DNA evidence properly can solve cases in ways previously only seen on TV. Much the way Trekkies envision a futuristic world of beaming molecules from one surface to another - law enforcement envisions the use of DNA evidence solving crimes faster, more reliably and more frequently than heretofore methods of fingerprinting, eye witness and the old fashioned "gum-shoe" work ethic of eras gone by.
Because of the uniqueness of each person's DNA, evidence collected at a crime scene can either link a suspect to a crime or eliminate a suspect. Further, whether blood, saliva or skins cells are collected - a person's DNA is the same throughout. DNA evidence can also identify a victim or suspect through samples obtained from relatives even when no body can be found. Crimes scenes can be compared across a State or Country and the same perpetrator identified if his/her DNA is present.
Forensically valuable DNA samples can be found on evidence that is decades old. However, several factors can degrade the viability of the sample including but not limited to heat, sunlight, moisture, bacteria or mold. DNA is found is blood, semen, skin cells, tissue, organs, muscle, brain cells, bone, teeth, hair, saliva, mucus, perspiration, fingernails, urine and feces - although most labs are loath to be testing feces looking for viable DNA samples and some of the private labs have discontinued offering such services.
Creative crime scene investigators can collect DNA evidence from non-traditional sources, such as saliva on cigarette butts or soda cans, sweat on baseball bats or a similar weapon, sweat inside a hat, bandanna or mask discarded at a crime scene, bite mark's containing saliva from the perpetrator, scrapings from underneath a fingernail (this we have all seen on TV shows like Law & Order or CSI). Today's crime scene detective has to visualize the crime and discern where and when DNA samples were transferred during the commission of a crime from perpetrator to victim; from perpetrator to scene surface etc., DNA profiles of those involved in the crime scene investigation (other than the perpetrator and/or victim) should be provided to the lab in order to eliminate possible contamination to evidence.
DNA collectors, laboratory personnel, lawyers and investigators should work as a cohesive unit to determine the most probative pieces of evidence and to establish priorities. Most state DNA laboratories are backlogged with evidence yet to be analyzed; however, there are many accredited and reliable private DNA laboratories that can be utilized in DNA detection and profiling.
Since biological material (DNA evidence) may contain hazardous pathogens such as HIV or Hepatitis B or the most recent H1B1 flu, care must be taken when collecting and/or handling samples. Given the nature of DNA evidence, officers should always contact a local DNA expert for answers about evidence collection.
Every State in the Nation has or is implementing a DNA index of individuals convicted of certain crimes - usually felonies (BARRMS + K - thanks to my college Criminal Justice professor). Upon conviction, the DNA sample is analysed and profiled and entered into a DNA Database. Just as fingerprints found at a crime scene can be run through AFIS (Automated Fingerprint Identification System) in search of a suspect or link to another crime scene, DNA profiles from a crime scene can be entered into CODIS enabling law enforcement officers to identify possible suspects when no suspect or lead existed.
Leave a comment