If you have ever watched a crime drama on television or read a best selling crime novel you have some idea what DNA is and how it is purportedly used to solve crimes. Is it really that accurate? How is it collected? If you are currently being investigated for a crime, or you have been charged with one, that allegedly involves DNA evidence, should you be worried? A Nebraska criminal lawyer answers these questions.
What Is DNA?
The acronym “DNA” is short for deoxyribonucleic acid, a self-replicating material present in nearly all living organisms as the main constituent of chromosomes. It is the carrier of genetic information for those living organisms, including humans. Your DNA can be found in blood, semen, saliva, urine, feces, hair, teeth, bone, tissue, and cells. Although 99.9 percent of human DNA sequences share the same in every person, enough of the DNA is different that it is possible to distinguish one individual from another, unless they are monozygotic (“identical”) twins.
How Is DNA Evidence Collected at a Crime Scene?
When a crime has been committed, the job of the responding law enforcement agency is to figure out and/or apprehend the perpetrator of the crime. The prosecuting attorney’s job is to bring the suspect to trial and secure a guilty verdict. To do that, the prosecutor needs evidence that the suspect did, in fact, commit the crime in question. A police offer might come across all different types of evidence during a search and seizure, including opportunities to collect DNA evidence. DNA might be extracted from common items such as clothing, weapons, glasses or bottles, hairbrush. If a person touched an object or weapon, skin cells may have been left behind. This low-level DNA is sometimes referred to as “touch DNA”. It can even be collected from a victim’s skin or bruises where they were handled roughly. Low-level DNA samples may be helpful when examining evidence where it would be difficult to retrieve fingerprints—such as textured surfaces on gun handles or automobile dashboards.
How Is DNA Evidence Used to Help Solve a Crime?
DNA left behind at a crime scene can only help if compared against a suspect’s DNA. To compare the victim’s or suspect’s DNA profile to the recovered crime-scene DNA, the laboratory will need to have their known biological samples available for a side-by-side comparison. These known samples are called reference samples. In some jurisdictions, a DNA sample is routinely taken from an arrestee during the process of booking and fingerprinting. The United States maintains the largest DNA database, with the Combined DNA Index System (CODIS) holding over 9 million records as of 2011. When DNA evidence is uncovered as part of a criminal investigation it will be run through CODIS to check for a match. Sometimes people close to the investigation will also be asked to voluntarily provide a DNA sample to exclude them as a suspect, or in the hope of finding the perpetrator. Because taking a DNA sample has long been considered a “search and seizure” by the courts, the police cannot force you to give a DNA sample unless the officer has first obtained a warrant signed by a judge.
Is DNA Evidence Accurate?
The accuracy of DNA evidence depends, in large part, on how carefully it is handled and which procedures are used compare the samples. Given the odds of anyone else in the entire world having your exact DNA are astronomical, unless you have a twin, it can be an excellent criminal investigation tool. When carefully handled it can be used to place a suspect at the scene of a crime. Of course, mistakes are made in the handling of DNA evidence which is why you need an experienced criminal defense attorney on your side if the State plans to use DNA evidence against you in a criminal prosecution.
Contact a Nebraska Criminal Lawyer at Petersen Law Office
If you have been charged with a criminal offense in the State of Nebraska, do not hesitate to consult with an experienced criminal defense attorney as soon as possible to ensure that your rights are protected. In Nebraska contact Petersen Criminal Defense Law 24 hours a day at 402-509-8070 to discuss your case.