While it is not common for prosecuting attorneys to call in expert witnesses to testify in a sex crimes case, it’s common enough that defendants should know the implications. There are many reasons attorneys usually don’t bother with expert witnesses. They can be expensive, there’s no guarantee that their testimony will help the case and sometimes it can be difficult to simply locate an expert witness. But if the prosecution decides to call an expert witness, it’s good to know what to expect.

What kind of experts do attorneys use in a sex crimes case?

Prosecutors will usually choose expert witnesses to reinforce key evidence for a conviction or elaborate on subjects that might be difficult for a jury to understand.

Gynecologists can explain evidence found on a female victim during a post-assault medical examination. Urologists might testify about urinary tract conditions found in women, men and children. Pediatricians consult when the victim is a child. A wide variety of forensic experts analyze everything from security camera footage to blood stains. Psychiatrists and psychologists will give testimony about the victim’s mental health after an assault. Each case is unique and will therefore have one or two key pieces of evidence that may require such expertise to drive those concepts home for the jury.

The pros and cons of expert witnesses

Attorneys will hire an expert witness when they believe the expert is in the best position to break down complex concepts, science and evidence into language that jurors and the rest of the court will understand. For example, the defense argues that the victim behaved in a questionable or confusing manner before, during or after the attack and the prosecution brings in a psychiatrist to explain why.

However, some attorneys believe that their clients would be better served by simply questioning regular witnesses and allowing the details of the case to unfold organically, which can be more persuasive.

It’s also common for attorneys to object to expert witnesses brought in by the opposing side, because their credibility may be too persuasive and overshadow evidence that helps their clients.

Do defense attorneys use expert witnesses, too?

Yes, there are instances when the defense might call in an expert witness. Defending against false allegations is a prime example. There are also situations when a victim faces charges stemming from acts committed while defending themselves.

More commonly, experts only assist attorneys in pre-trial preparation. These experts can contribute to case evaluation, jury selection and preparing someone for questioning.