DNA is a relatively new tool in the criminal field. However, despite its rather young age, the technology for identifying and using DNA has grown exponentially.
In fact, as technology has improved, DNA has helped to exonerate many people for crimes. Some people cleared through this process were even facing the death penalty. The Innocence Project explains DNA is incredibly effective evidence that can clear convictions in many cases.
One of the most important aspects of DNA is its uniqueness, but it is usually only a very small part of DNA that can distinguish one person from another. However, due to advances, technology can find that small percentage and draw it out to identify without a doubt the person to whom it belongs.
Because law enforcement keeps DNA databases, collected substances from a crime scene can go through this system to find a match and help officers to identify the correct suspect.
The first person who DNA cleared was Gary Dotson. He was in prison for kidnapping and rape stemming from a 1979 court conviction. He was facing up to 50 years in prison. The main evidence against him was eyewitness testimony, which is generally not reliable. After DNA testing, it was clear Dotson was not the guilty party. He was then a free man again.
Perhaps the best thing to come from DNA evidence is clearing the name of someone sentenced to death. Kirk Bloodsworth was the first person on death row to have DNA clear his name.
While DNA evidence is only helpful in cases where officers have DNA, it can be incredibly effective at clearing suspects and ensuring the wrong person does not end up behind bars.