An expert witness is an individual who is an expert in a particular field and they can offer valuable information in a criminal trial. They don't have to witness the crime in order to be a witness. All they have to have is an expert opinion about certain aspects of the case. And virtually any person who is an expert in a particular field can be an expert witness.

Types of expert witnesses

The most common expert witnesses are those working in the medical field. Doctors are frequently called in medical malpractice cases. They are also called forth in rape cases and murder cases. They know about various biological factors that a judge, lawyer, or a regular person may not even know. For instance, a murder trial may need a surgeon to talk about markings on the body before the murder. These could be surgery scars or some other sort of scar. It is important to point out these details even when they are not relevant to the murder itself.

Dentists will even be called in to talk about dental records, bite marks, skin found beneath teeth, and so much more. This can be very important to a trial. Perhaps a bite mark was thought to be the defendant's, but it is proved that the bite marks did not belong to the defendant. Then again, there may be skin found behind the teeth from biting the perpetrator and it is determined that the skin is not the defendant's. They may talk about bite mark patterns and so much more.

Medical examiners and coroners are also called upon the witness stand as expert witnesses so that they can talk about the things that they have observed. They may be asked if something is or is not possible. Their answer could be helpful or damaging to the defense. The idea is for them to provide an expert opinion on the things that have been presented to them. If they are unable to come up with a definitive answer, then they can state that.

What does it take?

First of all, the expert witness is an expert in a particular field that is relevant to the case. Again, doctors are the most common expert witnesses called into a case. But it must also be determined that they have no relationship with the person accused of a crime. If they are, then they could very easily alter their opinion in order to try to keep that person from being convicted. Usually, however, the prosecutor will still take statements from an expert witness that doesn't make sense and question them about their statement. But it is still important to determine that the expert witness does not know or know anything about the person who is on trial. That way all bias is completely eradicated.

From there, the expert witness simply has to know what it is they are talking about. They have to be one of the best in their field. When they are, they can take data that is presented on the fly and be able to make some educated determination on the witness stand. They are usually not presented with details of the case before giving their opinion so that they can give the most accurate answer possible. Although it may be helpful to go over some details, there are details that need to be kept at bay until the person is on the stand.

So now you know the role of the expert witness and how helpful they can be to a case. Without them, many determinations about a case would not be able to be made. Innocent people would be imprisoned and guilty people would be walking the streets.