An expert witness is someone who is called by either the defense or the prosecution to testify about a particular aspect of the case. They may testify by submitting a written statement or by appearing in court for questioning. In either scenario, the expert witness will have a chance to share their knowledge and how it applies to the case.
The Philadelphia criminal defense lawyers at our firm can determine whether hiring an expert witness would boost your case. We can also find the right witnesses to support your side of the story and provide a judge and jury with the information they need to make a fair decision.
What is an Expert Witness?
225 Pa. Code Rule 702 states that an expert witness can be anyone who has specialized knowledge of a topic that is both relevant to the case and beyond the scope of knowledge possessed by a layperson.
Examples of expert witnesses include the following:
- A medical doctor can speak to the most probable source of any injuries inflicted on the victim of a violent crime.
- A psychiatrist or psychologist can evaluate the mental state of various parties, including both perpetrators and accusers, involved in the alleged crime.
- A weapons expert can talk about the kind of gun that was used in the perpetration of a firearms offense and whether it matches any guns in the possession of the suspects or other people.
- A forensics expert can discuss the significance of evidence found at the crime scene, such as fingerprints or DNA.
- An accident reconstruction specialist can review the events leading up to a motor vehicle accident and determine whether or not illegal activity, such as drunk driving, was likely a contributing factor. Similarly, an expert on cars, motorcycles, or whatever vehicle was involved in the crash can contribute their knowledge to illuminate how and by whom each vehicle was damaged.
No matter what type of crime you are accused of, an expert may be able to help shed light on an aspect of your case that the judge and jury would not otherwise understand.
How to Hire an Expert Witness
Under the law, a witness can only be considered an expert if they are “generally accepted” to be one. That requires us to find someone:
- Who is educated, qualified, and accepted as an expert in their field
- Whose qualifications are accepted as genuine and relevant by the prosecution
- Who has the time and is willing to testify on your behalf
Criminal defense law firms like ours often have a network of experts in various fields that we call on whenever we need their expertise. Even if a particular witness does not have the time to provide an opinion or does not have knowledge directly related to a case, they may be able to recommend someone who is a better fit.
Once we find the right witness, we work with them to decide whether they want to submit a written opinion to the court or testify in person at your trial. Both methods can provide invaluable insight.
How Expert Witnesses Reach an Opinion
The witness must have access to all relevant materials and evidence. In a doctor’s case, this may involve conducting a medical exam or reviewing medical records, while an accident reconstruction specialist may have to visit the accident scene or examine the vehicles involved.
Our legal team can make sure the expert witness gets everything they need to form an accurate opinion.
Why Hiring Expert Witnesses is so Important
The judge and the jury members who will consider your case are all intelligent and thoughtful individuals, but that does not mean they possess the knowledge necessary to fairly decide your case. A good expert witness can:
- Explain complicated technical or scientific topics in an accessible way
- Add crucial context to situations that otherwise look suspicious or incriminating
- Tear down some or all of the prosecution’s case in ways that the jury might not have been able to consider on their own
- Project authority and confidence
In addition, the simple act of hearing an expert—or multiple experts—support your case can go a long way to convincing a jury that you have facts on your side. Since the jury does not have personal knowledge of the expert’s field, they will be looking for a competent authority to put their trust in—and we can provide that to them.
Contending with the Prosecution’s Expert Witnesses
Both sides in a criminal case are allowed to present expert witnesses to support their own positions. For example, while our defense attorney might bring in an expert to testify that it was not your car that hit a pedestrian, the prosecution may hire an expert who says just the opposite.
There are several ways to discredit or undermine testimony from the prosecution’s expert witnesses, including:
- Questioning their credentials. We can try to prevent their witness from testifying by showing that they are not qualified to speak on a particular subject.
- Cross-examining them on the stand. If the witness appears in person, we can ask pointed questions that spotlight holes or contradictions in their version of events.
- Identifying conflicts of interest. An expert witness can quickly lose credibility if they are not truly neutral. If there are any conflicts of interest, such as if they work for the same company as the victim, our defense lawyer can make the jury aware of this.
- Highlighting our own witnesses’ credibility. Even if the prosecution’s witnesses are credible and qualified, our legal team must show that our witnesses are even more reliable. This could persuade the jury to give more credence to our case and decide in your favor.
Learn More About How Expert Witnesses Can Strengthen Your Case
The Law Offices of M.J. Snyder, LLC, offers free consultations to everyone who calls our office. Our smart, aggressive attorneys know how to build strong defense cases by seeking information from expert witnesses and all other available sources of evidence. Contact us today so we have the maximum amount of time to put together your defense.
