Do Not Tell the Subject What You Know

Written By: Joseph P. Buckley
Jun 25, 2021

One of the most important principles of effective interviewing is to not tell the subject what you know about the details of the case, such as the information that you have developed from interviewing other subjects or from the evidence that you have developed up to the time of the interview.

Obviously at the outset of the interview the investigator will identify the issue that is under investigation – the death of the next-door neighbor; the fire in the warehouse; the missing deposit, etc. But rather than advise the subject of the information that you have developed to date and asking them if that is consistent with what they know or did, you should focus on asking the subject open-ended questions about what the subject did during the relevant time-period; what they know; what they saw; where they were at the time of the occurrence; etc. and evaluate whether the information the subject is providing is consistent with the information that you have developed up to this point.

For example, if in a homicide investigation you ask the subject when was the last time he saw the victim and he says that it was 7 or 8 days prior the subject’s death, and you have a video that was taken by a neighbor that shows the subject entering the victim’s residence just a few hours before the time of the murder, the subject’s failure to disclose that information would be highly significant.

On the other hand, if he readily tells you that he saw the victim on the day of her homicide, just a few hours before the apparent time of the murder, and explains the details of that visit, it would be much more suggestive of an individual who is being open and honest.

At the same time, you do not want to ask the subject questions that are predicted on information that you know. For example, in a case in which a million-dollar piece of equipment was sabotaged in a manufacturing facility, the investigator knew from a review of the company’s initial investigation that shortly after the sabotage was discovered, one of the employees went to his supervisor, Mr. Smith, and told him that he thought Patrick sabotaged the equipment because he had heard Patrick complaining about his wages, not getting the promotion he had been promised, and saying that the company would pay for mistreating him.

It would not be effective for the interviewer to say to the subject, “I see from the file that after this sabotage was discovered you went to your supervisor and told him you thought Patrick may have done this for these different reasons…..”

Rather, the investigator should ask the subject, “What did you do after you learned that this piece of equipment had been damaged?” and let the subject tell you that he went to his supervisor and told him about Patrick.

Consider the following case example. A bank teller (Mary Ann) experienced a $1,500 shortage in her cash drawer. On the day in question, she was the drive-up window teller. She stated the following to our investigator when she was asked about the sequence of events on the day in question:

  • · “I went in, and I pulled my drawer out. I counted out my drawer after I put it into my window and when I got done counting it, I had the need to order money and I had counted my large bills and I had $1,800 in large bills, and due to the way things were going I was obtaining more large bills than I was passing out. So not to keep so …. an over amount of money in my drawer I had paid out these large bills, thinking that I would obtain more throughout the day.”

So clearly, she is stating that based on her transactions she is taking in a considerable amount of large bills. So, she says that she takes $1,500 (ten $100 bills and eight $50 bills) and goes over to a colleague (Jane) who oversees the vault to sell the $1,500 back to the vault and obtain a $1,500 credit slip for her drawer. However, when she goes over to Jane, she is on the phone dealing with a customer, so Mary Ann returns to the drive-up window and places the $1,500 in a drawer in her work area.

Over the next 2 hours she is busy handling customer transactions at the drive-up window, and then, at about 9:30 she has a break in customer activity, so she opens the drawer to take the $1,500 over to Jane and discovers that the money is not in the drawer. She then goes over to Jane to confirm that she came over and took the $1,500 from the drawer, but Jane says she never had a chance to get over there to get the $1,500…..it has just disappeared. The subsequent bank internal investigation was unable to determine what happened to the missing money.

When our investigator interviewed Mary Ann he had her teller tape in his possession, which detailed the time of all her activities and transactions on the day in question, but he did not tell Mary Ann that he had the teller tape. So early in the interview he asked her to describe the sequence of events on the day in question…which she did as described as related above: “I went in, and I pulled my drawer out…..etc.”

However, later in the interview the investigator, referencing the teller tape, brought these entries to her attention:

  • Investigator: “And at 7:29 you entered the $1,500 transaction to sell.”
  • Subject: “To sell out, yes.”
  • I: “Why was it that at the time you bought the $2,000 you just didn’t give her the $1,500 at that time?”
  • S: “I was wrapping it.”
  • I: “Ok. Now your first transaction of the day doesn’t occur until 11:35, there’s a 6-minute gap there.”
  • S: “No that’s 7:35.”

So clearly she cannot be telling the truth - her first transaction was 7 minutes after she had entered the transaction to sell the $1,500 back to the vault, which earlier she said she did “because due to the way things were going I was obtaining more large bills than I was passing out”….she hasn’t had a transaction yet!!! The subject went on to acknowledge that she did steal the missing $1,500 and detailed how she spent the money.

If the investigator had advised Mary Ann at the outset of the interview that he had the teller tape, and reviewed with her the various entries she made, he would have lost the opportunity for her to offer her original story about "obtaining more large bills than I was passing out."

For more information on the use of open-ended questions during the interview visit our YouTube channel – The Reid Technique Tips, and specifically these two presentations: Using Open-ended Questions Part One and Part Two.

Permission is hereby granted to those who wish to share or copy this article. In those instances, the following Credit Statement must be included "This Investigator Tip was developed by John E. Reid and Associates Inc. 800-255-5747 / www.reid.com." Inquiries regarding Investigator Tips should be directed to Toni Overman toverman@reid.com.