What Does a Forensic Psychologist Do in a Criminal Case?

The challenge is to figure out who the defendant truly is.

Posted Nov 13, 2020

People often inquire as to what a forensic psychologist does. They derive their ideas about this subject mainly from television crime dramas. The dictionary definition of “forensic” states “relating to the application of scientific methods and techniques to the investigation of crime.”

As a forensic psychologist, I am not working at a crime scene or in a lab where other types of forensic investigations occur. A forensic psychologist deals with matters that come before courts, some relating to criminal conduct. (The next post will focus on child custody and visitation cases.) Forensic psychologists evaluate juvenile and adult defendants who are charged with crimes and subject to the jurisdiction of courts. I may be asked by a defense attorney or prosecutor to conduct a psychological evaluation of a defendant for a number of reasons. (A judge may sign an order for the evaluation.)

At issue may be the question of whether an adult or child charged with a crime is competent to stand trial. Does the defendant understand what he has been charged with? Does that person have a fundamental understanding of the proceedings that he will face? Does he understand the role of the judge, his lawyer, the prosecutor? Does he know what a trial is, the role of a jury, and what the possible outcomes can be?  Is he able to assist the attorney who will represent him? If I find that a defendant is not competent to stand trial, I must state whether there is a path for him to become competent and suggest how that might be accomplished. I may conclude that a person is competent to stand trial, but my finding may be contested. Then I testify before a judge who makes a determination.

There are other questions that I as a forensic psychologist am asked to address. If a defendant files an “insanity plea,” I may be appointed to evaluate his state of mind at the time of the offense. After a client has been found guilty of a crime, his attorney may ask that I evaluate him to present information to a judge that could impact the sentence that he receives. In the rare capital murder case, I may be asked to evaluate the defendant in terms of finding factors that would “mitigate” or lessen his sentence so that the death penalty would not be imposed.

The stakes of a trial are high for an individual whose life or freedom are on the line. As an “expert witness,” my job is to inform the judge or jury as to who the defendant is. This undertaking requires delving into a person’s life and understanding the individual’s psychological makeup before he committed the alleged offense.

With so much at stake, it is essential that I spend hours interviewing the defendant in-depth. In some complicated insanity cases, I have spent as many as 35 hours conducting individual interviews. Depending on the issues being explored, I might conduct psychological testing. A person could reasonably argue that a professional such as myself may not obtain accurate information from a defendant who might be self-serving because he seeks to minimize culpability and punishment. Therefore, I spend considerable time consulting “collateral sources,” or people who know the individual well. This could entail interviewing family members, relatives, neighbors, employers, clergy, household employees, and so forth. The scope of the task is comparable to trying to discover what a film of this individual’s life would look like. In a sense, it is like having a huge puzzle. Not only does the psychologist not know what the end result will be, but he has no idea at the outset as to how many pieces there are.

In addition to interviewing collateral sources, I review voluminous documents including “incident reports” by law enforcement officers about the offense, reports of witnesses, health and mental health records, job performance evaluations, driving records, the prior criminal record, school transcripts, crime scene and autopsy reports, records of behavior while in confinement, and financial records. I also view body camera videos, recordings of interviews by detectives, videos of the defendant while being arrested and transported in a police cruiser.

After conducting the evaluation, I write a comprehensive report of my findings. The prosecutor and defense attorney each obtain a copy. If asked to appear at the trial, I testify as to my findings. I am questioned directly by one attorney in what is called a direct examination, then cross-examined by the other who is looking for contradictions, inaccuracies, information not considered, and other flaws that might cast doubt on or discredit the process of the evaluation or the findings themselves. The forensic psychologist must respond by defending his position or acknowledging flaws or errors if they are present. During what is called “redirect,” the first attorney can pick up on questions asked during the cross-examination and give the psychologist a chance to clarify what he previously testified to.

There are skeptics about the usefulness of psychological testimony. Critics think that the “battle of experts” in some cases is more confusing than edifying for a jury. Some say that if a forensic psychologist is hired by a prosecutor, he will be expected to come up with a report favorable to that person’s side. The same with the defense. The process could turn into a contest between “hired guns” who seek to satisfy the person paying their bill. Although this may happen, I have experienced occasions when I have been retained by “one side” but actually my findings have been favorable to the other. In two recent “insanity” cases, I was retained by the prosecution but I concurred with the defense that the defendant met the criteria for insanity. Professional ethics and personal integrity demand that the forensic psychologist remains independent, no matter who hires him.