DNA stands for deoxyribonucleic acid. It contains the genetic instructions used in the development of human beings as well as most living organisms.
DNA evidence has been used to exonerate people who have been wrongly accused of crimes. It has also been used to prove people who have been accused of crimes guilty beyond a reasonable doubt.
People who are accused of crimes and told by police or prosecutors that their DNA has been found at the scene of the crime should not panic and believe that they will automatically be found guilty of whatever crime they are accused of.
Keep in mind the following facts about DNA:
1. It is transferrable. If you shake someone's hand, your hand will have that person's DNA on it.
2. It can mix with the DNA of another person. If you cut your finger and your blood comes into contact with the blood of another person and the "combined blood" smears onto an object, that object will have a mixture of both your DNA and the other person's DNA. If that very same object has been handled by a third person or many persons, the object will have many person's DNA which makes identification more difficult.
3. DNA is found in nearly every body fluid: blood, semen, saliva, etc. If body fluids from one person mix with the body fluids of another person, there is a DNA mixture which makes identification more difficult.
If you are accused of a crime in which DNA is part of the evidence against you, you must have your own forensic expert to interpret the evidence.
Fingerprint evidence, like DNA evidence, is not infallible.
Analysis of fingerprint evidence is highly subjective and too often wrong.
When fingerprint evidence is available, the defense must have their own expert to interpret the evidence.
Shoeprint evidence is even more subjective than fingerprint evidence. When the prosecutor has shoeprint evidence, defense should have their own expert.
SANE stands for Sexual Assault Nurse Examiner. Following the allegation of sexual assault, the alleged victim is often taken to the hospital and is examined by a SANE who has received special training.
The SANE examines the orifices of the alleged victim for trauma using special lights to show trauma that might not be seen by normal vision.
The SANE also takes swabs from the orifices of the alleged victim and marks and packages those swabs and puts them in a PERK.
Whenever there is a SANE report, the defense should spend significant time with the SANE to understand the report.
In rape or forcible sodomy case, usually, the defense should have their own SANE expert.
PERK stands for physical [or personal] evidence recovery kit.
When the SANE puts swabs into the PERK, the PERK is then picked up by someone form the police department who submits it to the division of forensic sciences for evaluation. The division of forensic sciences is looking for DNA or other evidence to identify the perpetrator of the alleged sexual assault.
The CSI Effect
Television shows like CSI have people thinking that if the police say they have your DNA or fingerprints or hair follicles, or something else that sounds "forensic" that you will automatically be found guilty. Not true.
Many times DNA found at the scene of a crime is a mixture of many people's DNA and cannot scientifically be linked to one particular individual.