DNA evidence can be found in our skin cells, hair, blood, or other bodily substances. It is unique to every person except for identical twins.
DNA evidence is one of the most reliable forms of evidence in criminal cases. Recently, many crimes committed before DNA testing have been solved. The smallest amount of DNA testing can be used to identify a criminal.
A Brief History of DNA Evidence
DNA testing was first used in 1985 by Alec Jeffreys, a British scientist. The first recorded case of DNA evidence solving a crime in the UK was in 1986. The USA started using DNA evidence shortly afterwards, and in 1987 it was used to convict a Florida rapist.
Any DNA evidence collected at crime scenes is preserved in evidence lockers. DNA evidence has exonerated many people who were wrongfully convicted of crimes before DNA technology was used to solve crimes.
Now law enforcement agencies have databases of DNA information to help identify crimes committed by known criminals. Sex offenders are now required to give police their DNA evidence to quickly identify them if they commit a crime. DNA evidence is examined in a lab, and many have large backlogs due to its popularity.
What Is DNA Testing?
DNA is present in all biological evidence like our skin, hair, and nails. The most common DNA evidence tested at crime scenes is bodily fluids.
The labs will use a PCR method so they can test small samples of DNA evidence. They can cross-reference these samples with DNA databases or against a DNA sample of a suspect.
DNA evidence is 99% accurate, and most of the errors come from human error, like mixing up or contaminating samples. To use DNA evidence in court, strict evidence gathering and testing rules have to be followed.
Other Uses For DNA Evidence
While DNA evidence is useful to convict criminals, it is also used to exonerate the wrongfully convicted. Over 250 people have been exonerated because of DNA evidence.
DNA tests are often used in paternity disputes or identifying the remains of victims of a crime.