The primary goal of an interview is to develop meaningful information from a subject. The first step in this process is to ask the right questions. However, merely asking the right questions will not guarantee that a subject will tell the truth. To learn the truth or to elicit behavior symptoms indicating probable deception it is often necessary to ask follow-up questions. While there are occasions when a particular response calls for a unique follow-up question, over the years we have observed that many responses to interview questions fit a particular category and, furthermore, that certain categories of answers suggest a particular follow-up question. Using the following rules, the investigator will walk out of an interview room with much more meaningful information.

Rule #1 When the subject's response to the initial question is evasive, find something within the response to agree with, and re-ask the original question.

Q: "Did you drive the company truck at all yesterday?"

R: "I didn't have any deliveries to make."

FO: "I understand that you weren't assigned any deliveries yesterday, but did you drive the company truck yesterday."

Principle: When a suspect evades a direct response to the investigator's question, this is an indication that the question caused anxiety within the subject. Because of this, the investigator certainly does not want to leave that area of the interview and pursue other topics, e.g., "Do you know who drove the truck?"; "Did you see any damage to the truck yesterday?" Rather, the investigator should re-ask the initial question in an effort to elicit a definitive response. To do this in a tactful manner, it is often helpful to introduce the follow-up question with a statement that agrees with some aspect of the subject's original response.

Rule #2 When the subject's response includes an inappropriate memory qualifier ask, "Is it possible..."

Q: "Have you handled a gun in the last two weeks?"

R: "I don't believe so."

FO: "Is it possible you handled a gun in the last two weeks?"

Principle: There are a number of common phrases referred to as memory qualifiers. Examples include, "To the best of my knowledge," "As far as I remember," "I believe," and, "If my memory serves me correctly." If the investigator's question addresses a common occurrence that happened in the distant past, the subject's use of a memory qualifier may be very appropriate. However, when the subject should reasonably know the answer to the investigator's question but, nonetheless, incorporates a memory qualifier within their response, this is an indication that the subject is either not a bold liar or is concerned that evidence may surface that will contradict his response. In either situation, it is often productive to ask the hypothetical follow-up question "Is it possible." In many instances, this follow-up question has resulted in the subject acknowledging that possibility.

Rule #3 When the subject offers a specific denial, ask follow-up questions that address what the subject is not denying.

Q: "Did you cause the injuries to your wife?"

A: "I didn't strike her with anything!"

FO: "Did you hit her with your hand or fist?"

FO: "Did you push her down?"

FO: "Did you kick her?"

Principle: A guilty suspect knows exactly what he did or did not do during the commission of his crime. To avoid lying to the investigator's questions, the suspect may deny some narrow aspect of the question. This is called a specific denial. In the above example, the husband is probably telling the truth when he specifically denies striking his wife with anything, e.g., an object. However, this does not mean that he is not responsible for causing his wife's injuries. The investigator needs to ask follow-up questions that address other possible ways that the husband may have caused the injuries.

Rule # 4 When a suspect asks the investigator to clarify an interview question, in most cases the original question should be repeated word for word. The one exception to this may be if the investigator's original question was confusing or ambiguous.

Q: "Were you involved in an accident last Friday on Madison Street?"

R: "What exactly do you mean?"

FO: "What I'm asking is whether or not you were involved in an accident last Friday on Madison Street."

Principle: The most common reason for a subject to ask an investigator to clarify a question during an interview is to buy time to formulate a non-incriminating response. In other words, when a subject requests that a straight-forward question be clarified this is typical of the guilty person. In addition, a subject may request that an interview question be clarified in the hope that the clarified question will be an easier question to lie to. Consequently, unless the original question was confusing or ambiguous, the "clarified" question should be identical to the original one.

Rule #5 When a subject's response includes a time-gap phrase such as "The next thing I recall," or, "Before I knew it." the investigator should pursue details surrounding the time period just before the use of the time-gap phrase.

Q: "Explain how you received your injuries."

A: "I was minding my own business and this cop came over and hassled me. The next thing I knew I was on the ground and he was kicking me in the stomach."

Q: "Tell me more about what happened just prior to you being on the ground."

Principle: Time gap phrases are red flags within a response which indicate that the subject is consciously leaving something out of the response. This edited information may be sensitive, embarrassing or incriminating. To evaluate the significance of the edited information, the investigator needs to draw out more detailed information concerning that portion of the subject's response.

Rule #6 When a suspect makes any admission to the investigator's question, the automatic follow-up question should be, "Other than (admission) ..."

Q: "Have you ever been asked to leave a job?"

R: "When I was sixteen I worked in a sandwich shop that was about seven miles from my home and I had a hard time getting to work on time. After being late on a number of occasions they let me go."

FO: "Other than the sandwich shop, have you been asked to leave any other job."

R: "Actually I was. For a short period of time I worked as a messenger and there was some confusion about what happened to some money I was supposed to deliver."

FO: "Other than those two jobs have you been asked to leave any other jobs?"

R: "Come to think of it there was a misunderstanding with my last job..."

Principle: Omission (failure to volunteer the entire truth) is such a common occurrence in our society that it is not even legally considered a lie. To be guilty of perjury or obstruction of justice, it must be proven that the defendant knowingly offered false information. The subtle distinction between lies of omission and commission is not lost on subjects during an investigative interview. Without question, the easiest way to keep an investigator from learning the whole truth is by offering a small part of the truth through a non-incriminating statement. To learn the whole truth, the investigator must stick with the present line of questioning until the suspect offers a definitive denial.