Should I Hire an Expert Witness for my Criminal Case?

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Should I Hire an Expert Witness for my Criminal Case?

The most common form of evidence in criminal trials is lay witness testimony.  Typically, the state will call witnesses to the stand that personally observed an alleged crime.  Prosecutors will ask the witness what the witness observed, heard, or perceived.  The factfinder (judge or jury) will then place whatever weight they deem appropriate on the witness testimony in conjunction with the other evidence presented at trial.

There are times when expert witnesses are called by either the state or defense.  An expert witness is a person that has specific knowledge or skills in a field that is relevant to the case.   The rule governing expert testimony is Indiana Rule of Evidence 702.  It provides that:

“A witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if:

  • The expert’s scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue;
  • The testimony is based on sufficient facts or data;
  • The testimony is the product of reliable principles and methods; and
  • The expert has reliably applied the principles and methods to the facts of the case.”

The point of an expert witness is to educate the judge or jury about a complicated topic.  For example, in murder cases, the prosecution will nearly always call a forensic pathologist as an expert witness to testify about their findings in an autopsy.  For instance, the pathologist could testify about their opinion as to entrance and exit bullet wounds.  This testimony could help further the prosecutor’s theory of the case as to where individuals were located or how people were situated when gunshots erupted.

The Defense might similarly rely on the testimony of a forensic pathologist.  For example, in a case in which the defendant is asserting self-defense, the pathologist could testify about the toxicological examination performed as part of the autopsy.   If the decedent had high levels of alcohol and cocaine in their system at the time of death, the pathologist could testify that this combination could generally cause a person to become much more violent, hostile or irritable than normal.  This information might help the defendant prove that it was the decedent, and not the defendant, that was the initial aggressor in the altercation that led to the decedent’s death.

Under both of the above scenarios, the expert witness is providing testimony about topics that may not be known by the community at large.  In the first scenario, the pathologist is testifying about their knowledge and skill as it pertains to measuring and identifying bullet wounds.  In the second scenario, the pathologist is testifying as to their knowledge about the effects of drugs and alcohol on a person’s psyche.  Clearly, convincing testimony from an expert can drastically impact the outcome of a criminal trial for either the prosecution or defense.

Do you have a case in which you believe hiring an expert would be beneficial?  We are happy to help.  Contact the experienced trial attorneys at Banks and Brower anytime at 317-870-0019 or by emailing at