3.2-A. Work with Experts to Understand and Explain the Evidence
Consider which experts, if any, will assist you in understanding the significance of the evidence and explaining it to the jury. Experts can help the prosecutor understand the results of a SAK examination or other medical reports, toxicology results, or forensic evidence (e.g., DNA or the results of a forensic examination of a cell phone). They can also help explain issues commonly misunderstood by juries — victim behavior, the effects of trauma, offender tactics, cultural factors impacting victimization, etc. Expert testimony can assist the jury in reaching an informed verdict based on the evidence rather than myths or misconceptions.
Early consultation with experts ensures your case is prepared with as much information and context as possible. Consultation is useful even if expert testimony is not anticipated. In considering whether expert testimony may be necessary, consider the following:
- Medical, forensic/technical, or toxicology evidence will usually require expert testimony —for example, jurors should not speculate what a .3 blood alcohol content (BAC) means for a person’s ability to consent, perceive/recall events, or engage in other activities. Nor should they be asked to conclude on their own whether injuries are consistent with the victim’s account of the attack. See Appendix F on Considerations for Working with Experts and Appendix G on Stages of Acute Alcohol Influence/Intoxication.
- How effectively can the victim explain his or her own behavior during and after the assault? How understandable would the explanation sound to someone untrained in sexual assault dynamics and victim responses to trauma?
- Are there other factors that jurors might find confusing or troubling, such as an absence of visible physical injury? Were there tests, examinations, or analyses not performed because they were deemed unlikely to produce any useful information? The significance of the absence of certain types evidence should be explained by an expert to avoid jury speculation.
- Also consider whether an expert is appropriate for a specific case and/or jury as well as the costs of retaining an expert.228
Meet with potential expert witnesses in person, well in advance of trial, to discuss their qualifications, the content of their proposed testimony, the scientific foundation for their opinions if necessary, and the content of any mandatory expert report.229 Obtain the expert’s most recent C.V., which should be provided to the defense.
File appropriate and timely motions to introduce expert testimony.230 See 3.3-G for tips regarding the introduction of expert testimony at trial. Provide appropriate notice to the defense and the court so any disputed issues can be resolved well in advance of trial.
Become familiar with your jurisdiction’s evidentiary rule on expert testimony231 as well as any case law governing the admissibility of expert testimony on victim behavior, SAKs, toxicology, DNA, etc.
The admissibility of expert testimony to explain victim behavior varies widely across jurisdictions; in conducting legal research on the caselaw, search for cases involving both child and adult victims of sexual assault, as well as victims of domestic violence – including cases involving the admissibility of expert testimony on the behalf of defendants who raise battering or abuse as a defense.
Another analogous type of expert testimony is that of specially trained or experienced police officers who testify about drug distribution or gang activity. Determine whether the admissibility of a specific type of expert testimony is governed by Daubert or Frye.232 Absent authority (statutory or caselaw) from your jurisdiction, research other jurisdictions with similar evidence rules that may have persuasive caselaw.
Discuss with your expert how to respond to defense requests for an interview.233 The expert, like any other witness, is free to agree or refuse an interview by the defense, but refusal may result in defense suggestions of bias when the expert is cross-examined at trial. You can ask the expert to let you know if the defense contacts them and what was discussed, which may provide some insight into defense strategy or possible weaknesses that should be addressed with the expert before trial.
It is advisable to be familiar with the proposed expert’s social media activity. The defense is likely to research the expert’s online activity, and any posts regarding specific cases or sexual assault allegations are usually fair game for cross-examination — for example, to support a claim of bias. Any troublesome posts should be discussed with the expert so you both are prepared to respond to such questioning at trial.
The defense may be planning to present expert testimony, as well, either to rebut or undermine the testimony and conclusions of the prosecution’s expert(s) or to support a defense such as intoxication or mental disease/defect.
- If the defense is presenting expert testimony in support of a defense, you will usually want to present your own expert in rebuttal. Find one and prepare that expert as you would one called in your case in chief.
- The defense is required to provide pretrial notice of an intent to present expert testimony. If you have not received notice of intent to call an expert, inquire on the record during a pretrial conference or hearing whether the defense will be calling any experts. If the answer is “no,” then any attempt to present expert testimony during trial should be barred. If the answer is “yes,” insist upon a deadline, well in advance of trial, for production of the expert’s C.V. and a report or summary of the proposed testimony.
- Consult with your expert to review the report or summary from the defense expert.
- Use your expert’s suggestions to prepare for an interview of the defense expert.
- Review the defense expert interview with your expert afterwards, and follow up with the defense about any unresolved issues.
- If the defense expert refuses to meet with you, prepare to cross the expert on that issue (assuming, of course, that your own expert was responsive to the defense’s request).
- Carefully inquire of the defense expert the basis for their opinion, e., the information or authorities relied upon. Was the expert provided with only selected reports or statements? Does the opinion rely solely on the defendant’s version of what occurred? Does the expert accept the authority of widely recognized experts in the field?
- Prepare to challenge the defense expert’s qualifications prior to trial. Research the defense expert’s professional history and training, and find out from other prosecutors, including those in nearby jurisdictions, whether they are familiar with this expert and their qualifications. For example, a general medical doctor with no specific training or experience in sexual assault forensic exams would lack the requisite expertise to provide an opinion concerning the significance of absence of physical injury.
- If the challenge is unsuccessful, prepare a cross-examination to highlight the defense expert’s deficiencies in expertise, unfamiliarity with the area’s wide scope of literature, and degree to which the opinion contradicts scientific consensus on the issue. Your expert should be able to suggest areas for cross-examination of the defense expert at trial.
The below sections briefly discuss the types of issues that will arise in a case and how experts can help prepare the case and provide testimony at trial. See Appendix F to help identify experts who can assist with specific issues that may arise in a case.
3.2-A-1. Victim Behavior234
Public perceptions about how victims should respond to physical and emotional trauma often conflict with their actual responses, and such misconceptions can significantly impact juror assessment of victim credibility. Victims have individual responses to trauma; different victims could survive the same attack and have very different reactions.
It is important to communicate to the jury that there is no “typical” response. Consider whether a victim behavior expert witness would be beneficial in your case, given the facts and the victim’s ability to explain her/his own behavior.
Remember, too, that identifying an expert and putting that expert on your witness list does not commit you to presenting that expert testimony; you can make the final determination about the need for expert testimony after the victim testifies.
Professionals you might consider calling as experts in victim behavior include:
- Psychiatrists and psychologists
- Law enforcement
- Healthcare professionals (g., SANE)
Experts in victim behavior should not be asked to provide an opinion as to whether the victim in this case was sexually assaulted, a victim of trauma, or truthful in their report or testimony; this applies to defense experts as well, and prosecutors should object to any attempts to introduce this type of testimony. Rather, they should be used to educate the factfinder by describing, in general, the varied responses to trauma during and after a sexual assault.
To maintain victim privacy and the integrity of the case, do not use a victim behavior expert who has been working with the victim – such as the victim’s own advocate, counselor, or therapist. Doing so would blur the lines between the experts’ testimony on victim behavior and an assessment of the victim’s credibility; it would also open the door to defense requests to examine the victim’s counseling records.
Most jurisdictions have clear rules or caselaw permitting expert testimony to explain victim behavior, but it is still important to carefully review statutes and caselaw to determine what type of experts are permitted to testify and the scope of that testimony.235
Like any other expert, victim behavior experts must be qualified, but their qualifications may be accepted largely on the basis of their training and experience, rather than by standards more strictly applicable to scientific evidence.236