There are many types of evidence that are commonly used at trial, including items found at the crime scene and eyewitness testimony. Scientific and forensic evidence can be extremely helpful in proving your case, since they can often reveal otherwise hidden clues about the incident. However, there are rules and standards that these types of evidence must meet before they can be submitted during a trial.
The following provides an overview of scientific and forensic evidence as used in criminal trials.
You may be wondering what on earth scientific evidence could mean in regards to a trial. In general, scientific evidence is based off of knowledge that has been developed by using the scientific method. This means that the basis for the evidence has been hypothesized and tested and is generally accepted within the scientific community. This could mean that the theory on which the scientific evidence is based has been published in scientific journals and has been subjected to peer review within the scientific community.
Generally, many types of forensic evidence are often considered scientific evidence, like DNA matching, fingerprint identification, and hair/fiber evidence. The methods used to develop these types of evidence are generally beyond the scope of knowledge that judges and juries possess and are therefore normally introduced as scientific evidence.
Although scientific evidence can strengthen a case, it may be excluded from a courtroom or trial in some instances. There are often many steps that must be taken before it can be put forth in a courtroom as factual evidence. In general, a scientific theory must have established itself in the scientific community and become generally accepted as the truth before it will be asserted as evidence at trial.
For example, because it has been around for so long and because it has proven to be reliable, evidence regarding fingerprint matching is generally admissible as forensic evidence in trial. In addition, things like radar and laser speed guns are generally accepted as being a valid method to tell the speed of a car at a given time and can be admitted as evidence. But keep in mind that there will often be new types of scientific evidence that parties will attempt to submit at trial -- science that may not have a solid foundation within the scientific community.
If one side of a trial wishes to submit scientific evidence that is not yet generally accepted within the scientific community, it often happens that the court orders a mini-trial to be held in order to determine the validity of the scientific theory on which the evidence is based. As an example, DNA evidence had to go through many mini-trials before it became generally accepted as valid evidence at trail.
In the future, we may see more mini-trials as more types of forensic evidence are introduced in court. As another example, many scientists are currently working on using functional Magnetic Resonance Imaging (fMRI) as a new type of lie detection machine (this works by imaging, in real time, the flow of blood around the brain). If, during a mini-trial, a judge can be convinced that a new, as-of-yet unproven, type of scientific evidence should be introduced at trial, then the judge will allow it to be presented.
Believe it or not, there are ways to challenge scientific and forensic evidence, such as attacking the chain of custody of blood samples or the improper calibration of a radar gun. Many criminal defense attorneys specialize in scientific and forensic evidence and can call on expert witnesses in your defense. See what options are available to you by contacting a local defense attorney today.
