An interview is designed not only to collect and gather information but to assess the credibility of the person offering that information. In some instances the investigator will have clear evidence to validate a subject's information such as surveillance video, documents or forensic evidence. Oftentimes, however, such evidence does not exist and the investigator must rely on interviewing techniques and behavior symptom analysis to assess a person's credibility. To elicit meaningful behavior during an interview requires that the investigator be perceived as an objective and unbiased observer. On the other hand, if it is apparent that the investigator strongly wants to believe a subject then false information can easily be accepted as the truth. Similarly, if an investigator approaches a subject as someone who is a liar, that expectation too, will be fulfilled.
This does not mean that it is improper for an investigator to form a preconceived expectation of a person's truthfulness prior to an interview. Investigators are trained to analyze factual information such as motives, opportunity, access, propensity and evidence and a good investigator oftentimes will form probability estimates of a person's involvement in a crime prior to an interview. These initial assessments, however, should remain at the cognitive level and not be conveyed to the subject during an interview. The dangers of allowing preconceived expectations to surface during an interview is revealed in this recent consultation:
A mother convinced her 19-year-old daughter to contact police regarding repressed memories of sexual abuse committed by the mother's ex-husband (the daughter's natural father). During the audio-taped interview the daughter reported one actual memory of sexual abuse involving her father touching her vaginal area while she was in bed with him. When asked about having sexual intercourse with her father the daughter denied remembering such an occurrence, yet stated that she "must have had sex with him" because on one occasion she "hurt" the next day. The investigator never asked what she meant by hurting (vaginal pain, emotional injury, etc.) but rather continued the interview under the assumption that the woman had intercourse with her father. Through the use of leading questions, the investigator eventually got this woman to state that she had sexual intercourse with her father approximately 10 to 15 times. During the course of this interview either the woman's memory was magically restored or she felt comfortable telling the investigator information he was anxious to hear, even though it was not based on factual recall.
Other factual information in this case supported probable sexual molestation (of some nature) by the father. A definite fact, however, is that at the time of the interview the woman had no specific recollections of having sexual intercourse with her father, yet multiple allegations of sexual intercourse were listed in the criminal complaint. For whatever reason, (pity toward the woman, hatred toward the accused father) this investigator lost his objectivity and included unsupportable information in the criminal complaint.
Whether the subject of an interview is a victim, witness or a suspect, it is improper to assume that the person will tell the truth. The investigator must reinforce the importance of telling the complete truth so the subject knows what is expected of him or her. Early during an interview it is often productive to make a statement to the subject emphasizing the investigator's objective role during the investigation. In the repressed memory case, a possible statement would be as follows:
"Linda, let me explain what will happen this afternoon. I understand that there are some things you would like to tell me about your father and we will talk about that. My role as an investigator is to collect and analyze information. I don't judge people as good or bad or decide what an appropriate punishment might be or anything like that. I simply collect information, but the information I collect all has to be truthful. I know you have probably talked to your mom and other people about your father and that's fine. I don't care what you've told other people but it is very important that everything you tell me today is based on things you actually remember and that you are 100% certain really happened."
A standard opening statement we make for all suspects we interview is similar to the following:
"Jim, during this interview I will be asking you questions about (issue under investigation). Some of the questions I'll be asking you this afternoon I already know the answer to but the most important thing is that you be completely truthful with me before you leave here today. If you (did issue) our investigation will clearly indicate that but if you had nothing to do with this, it will show that as well."
During our seminars we show interviews of both truthful and deceptive subjects. Prior to each of these interviews the investigator has formed an expectation probability of the person's guilt or innocence based on available factual information. However, when viewing these interviews participants would have no idea whether the suspect was considered to be more likely truthful or deceptive. In other words, the investigator's demeanor, tone of voice, questions and questioning style were not at all affected by their initial assessment of the subject's probable truthfulness.
There are statements an investigator should avoid making during an interview because they suggest a bias in his expectation of the subject's perceived truthfulness. Some of these statements include:
1. Demeaning the suspect, "I deal with slugs like you every day."
2. Challenging a suspect, "That's not what you told the other investigator o don't lie to me."
3. Validating a victim's account, "I know it is difficult to discuss being assaulted but I still have to ask you some questions." [Note that this investigator has fully accepted as a fact that the victim was assaulted]
4. Pardoning the suspect, "I don't think you had anything to do with this but I would still like to ask you some questions." [Note that the probably innocent person who has been told that he or she is not a suspect in the investigation has little motivation to reveal sensitive information that could contribute to identifying the guilty person. Innocent suspects volunteer helpful information because they do not want the investigator to believe they committed the crime.]
The investigator's demeanor during an interview can also transmit a bias to a subject. In the case of a suspect, an accusatory tone of voice may signal to the suspect that the investigator is already convinced of the suspect's guilt and cause the suspect to become defensive and offer little information or to request an attorney. A sympathetic tone of voice accompanied with positive head nodding may signal to the deceptive witness or victim that their false story is being fully accepted.
Persuasion vs. Objectivity
When an investigator uses active persuasion during an interrogation in an effort to convince the suspect, victim or witness to tell the truth, clearly the investigator's outward demeanor is no longer objective. Under this circumstance a statement has been made to the person being interrogated that the investigator believes that he or she has lied. This raises the question of whether or not persuasive tactics can be properly used during an interview without jeopardizing the investigator's objectivity. Under some circumstances an investigator must engage in passive persuasion to encourage a suspect, witness or victim to tell the truth during an interview as the following examples illustrate:
Telling a suspect that the stolen vehicle is being dusted for finger prints and if his prints are found in the car it will prove he was in the car;
Implying possible evidence by saying, "Think carefully before you answer this next question";
Reassuring a reluctant witness that retaliation is very rare and that their cooperation will get the threatening person off of the streets;
Telling a sexual assault victim that you talk to women on a regular basis about sexual matters and that there is nothing she could tell you that you have not heard from other women;
Suggesting exaggerated answers to a question when the subject delays his response, e.g.,
Inv: "Were you drinking at all that night?
Inv: " Did you have like 15 or 20 drinks?"
An investigator must appreciate what his or her role is in the adversarial system. It is not the investigator's job to prove that a particular person is guilty of a crime o that responsibility falls onto the prosecutor. It is, however, the investigator's responsibility to make certain that any incriminating statements made during an interview or interrogation are legally obtained and represent the truth. Similarly, it is the investigator's responsibility to make a reasonable effort to establish that a witness or victim's statements are the truth and to fully investigate a crime. At a minimum, this latter effort should involve fully exploring a suspect's alibi and making a reasonable effort to eliminate other possible suspects in the crime. If these two criteria are followed many individuals who, through DNA results were later proven to be wrongly convicted of a crime, would never have gone to trial. The investigator and judge are the only truly objective members in our adversarial system and efforts to learn the truth should not abruptly stop once a person confesses or is charged with a crime.
For more information on interviewing victims consider attending our three day course on child abuse investigations.