During our training seminars we advocate that if the option is available it is preferable to conduct a non-custodial interview rather than a custodial interview. To persuade a guilty subject to voluntarily agree to present himself at the investigator's location for an interview requires that the interview be introduced in the proper manner. A past case clearly illustrates an improper approach:

A business owner suffered a theft of $2000 from a deposit bag that was left in a back office. Seven employees had access to the stolen money. The owner called a meeting of these employees and announced that if the person who stole the money came forward by Monday there would be no prosecution. On the other hand, if no one came forward all employees would be subjected to lie-detector tests and when the guilty person was identified, he would be prosecuted to the full extent of the law. Needless to say, no one came forward and confessed. When the polygraph examinations were scheduled several of the employees refused to take the examination, which was their legal right, and the case was never solved. Because of a general lack of insight to human behavior, the business owner unknowingly created a situation which almost guaranteed that the employee who stole the $2000 would not be detected.

The following guidelines are offered to assist an investigator, or business owner, to encourage suspects of a crime to voluntarily agree to be interviewed:

Guideline #1: Never threaten a subject with possible consequences if he is involved in the crime, or if he does not show up for the interview. It is psychologically wrong to remind a subject that if he cooperates with the investigation he may well be convicted and go to prison. Most people who commit crimes are chance-takers. They will generally accept the risk of cooperating with an investigation unless the presented stakes are so high (threatened prosecution) that they out-weigh the risk of cooperation. Secondly, it is legally improper to threaten the subject with possible arrest, or some similar tangible consequence, if he fails to agree to be interviewed. A subject who presents himself for an interview in order to avoid being arrested (or keep his job) is hardly answering questions voluntarily.

Guideline #2: Present the interview in a positive light. To understand this guideline it is appropriate to ask, "Why would any person guilty of a crime agree to take a polygraph examination or agree to be interviewed by the police?" There are two basic reasons. One is that the person is afraid that his refusal to cooperate will make his guilt more apparent. A second reason, and one that applies to many guilty suspects, is a need to maintain full personal control of one's destiny; this translates to the guilty suspect's drive to "beat" the polygraph or to lie convincingly during an interview. To feed this belief the investigator should present the interview as a means by which the subject can be cleared from suspicion. Most certainly, during an invitation to be interviewed a subject should not be told that there is strong evidence implicating him in the crime. To the contrary, the intimation should be that the subject's name came up peripherally during the investigation. In some situations an altruistic appeal may be effective, where the subject is told that because he knows some of the people in the investigation his insight would be very helpful. In the previously mentioned employee theft case, a much different outcome may have resulted had the employer stated, "I realize that it is unlikely that any of you took the money but to obtain reimbursement from my insurance company they are asking that you all take a polygraph examination."

Guideline #3: Imply that others also have been, or will be interviewed and avoid discussing specific evidence against the suspect. A guilty suspect is unlikely to appear voluntarily for an interview if he believes that he is the prime suspect and, therefore, the only person to be interviewed on the case. Under that circumstance, in his mind, the proposed interview is nothing more than a ruse designed to elicit a confession. Similarly, the phrase, "We would like you to come downtown to answer routine questions" should be avoided. If the questions were routine, they could be asked at the present time.

On the other hand, by stating that others also will be or have been interviewed allows the guilty suspect to feel comfortable cooperating with the interview procedure because he is surrounded by other possible suspects. Avoiding any mention of evidence pointing to the subject permits the guilty subject to believe that there is no solid evidence against him and that the interview is a mere formality of the investigation.

Guideline #4: Be prepared to explain why the interview must be conducted at your location. Given a choice, most subjects would prefer to be interviewed in a familiar surrounding such as their home or place of business. This environment, of course, is often not conducive for the investigator. One way around this dilemma is to contact the subject by phone to set up the interview in the investigator's office. However, telephonic communication does not have the same persuasive effect of talking with the suspect directly. During a face to face invitation for the interview the investigator should have a prepared response to offer when the subject suggests that the interview be conducted at the present time. Some excuses to consider for scheduling the interview in the investigator's office may be that your partner needs to be present, you do not have the case file with you, or that a departmental policy requires that investigative interviews be conducted in your office.

The following dialogue incorporates these guidelines and is designed to obtain the cooperation from the subject to show up at a scheduled time for a non-custodial interview:

I: "Rick, we are looking into the incident last week where that school girl was shot by someone in a car. During the course of our investigation, we have developed a number of leads and people's names. Yours was one of them."
S: "Alright."
I: "What we have done is to schedule these people for interviews to eliminate them as possible suspects. In fact, everyone who has come in for their interview so far we've been able to eliminate. What we're hoping is that one of these people will have seen or heard something that can help us out. Would you mind coming to our office for an interview?"
S: "Well, I don't know. Why don't you just ask your questions now because I don't know anything about that."
I: "When we have direct evidence pointing to a person we will interview them in their home. But we're at an early stage of the investigation so all I'm doing today is arranging interview times. I've got three people to schedule after you. Now you work until 4:00 is that right?
S: Yeah.
I: "I'm wondering if you could make it by 4:30 tomorrow afternoon."
S: "How long will it take?"
I: "The other interviews have lasted less than an hour."
S: "Sure. I'll be there by 4:30."
I: "Great, we'll see you then."

As a legal consideration, it is certainly preferable for the subject to arrange his own transportation to the investigator's office. A subject who is transported to the office by the investigator is somewhat limited in his ability to freely leave the office area. If the subject is transported to the office by an investigator it will be important for that investigator to remind the subject that he is there voluntarily and is free to leave at any time.