[Editor's note: The following article is excerpted with permission from chapter 22 of the third edition of The Process of Investigation: Concepts and Strategies for Investigators in the Private Sector, published by Butterworth-Heinemann, and authored by Charles Sennewald and John Tsukayama. The book is useful as a reference guide, though the clarity and readability of the book makes it a useful self-study text for any security director or corporate investigator looking to hone his or her skillset. The following section is from a paragraph that was authored by David Zulawski and Douglas Wicklander, and which appeared in Sennewald and Tsukayama's text with permission from Wicklander-Zulawski & Associates.]
There are a number of different ways to conduct an interrogation of a suspect. The interrogatorâ€™s selection of an interrogation method often is based on the background of the suspect, amount of evidence available, and possible response of the suspect to the interrogation. In instances where a number of people were acting together to commit the crime it may be useful to have multiple interrogators available to confront all of them at one time. It usually is preferable to conduct the interrogation in a surprise fashion, rather than alerting the suspects that they are going to be questioned.
Preparing for the interrogation requires that the interrogator had sufficient rooms, interrogators, witnesses, and resources to handle the number of suspects involved in the incident. In larger cases, such as organized theft rings, this may become as much of an administrative problem as an interrogational issue.
In cases where extensive factual information and evidence is available to the interrogator he may elect to use a factual approach. However, when considering whether to use a factual attack the interrogator should evaluate the amount of evidence available and whether or not it should be revealed to the suspect. In some instances revealing the evidence may compromise informants or other ongoing investigations.
The most effective use of evidence is to contradict statements or assertions previously made by the suspect. The interrogator should ask the suspect questions to which he will likely lie to conceal his involvement in the incident. Once the suspect has been sufficiently locked into his story or alibi the interrogator can now begin to dismantle it using the evidence discovered during the investigation.
The evidence is presented in a nonemotional fashion by the interrogator. The interrogator offers a piece of evidence that contradicts a previous statement by the suspect and asks for an explanation from the suspect. The interrogator usually starts with seemingly insignificant pieces of evidence that are at odds with the suspectâ€™s earlier statements. The suspect at first usually will attempt to explain away the evidence until it becomes evident to him that he has been caught as the contradictions mount.
An interrogator using a factual attack generally will get an admission only to the incident he already knows about and not other areas of involvement. The use of facts establishes to the suspect what his area(s) of exposure are and also tells him what the interrogator likely does not know. This then limits admissions into other areas of wrongdoing that were unknown to the interrogator. A second consideration is that using a factual approach alone, without rationalization, means that the suspect must admit to the crime and to the fact that he is a bad person. Combining rationalization with a factual approach often makes it easier for the suspect to confess since he is able to save face.