Essential for Investigations: Interview and Interrogation Techniques


Knowledge and experience concerning interview and interrogation techniques are still among the most important tools for private or corporate investigators. An expanded training in this regard is therefore essential.

During an investigation, there is often a lack of physical evidence to advance or even solve the case. In these situations, a classic and established method comes into play to gather new information: the interview or interrogation. Since we often deal with international investigations nowadays, interviews are less often conducted face to face but more likely on the phone. Many interviews are also conducted in English, which can lead to problems, especially when English is neither participant’s mother tongue.

Structured Interrogation

At any rate, a well conducted interrogation takes a lot of skill. There are several different methods and models, but particularly for beginners the structured interrogation is most suitable.

Preparation of the Interview

  • Determining the aim of the interview
  • Intense knowledge of the circumstances, visualization (i.e. timeline or relation chart)
  • What needs to be clarified and with whom?
  • Preparation of the setting

Contact and Orientation

Forming a relationship, setting the rules

Free Report

Uninterrupted report by the respondent


Clarification using specific questioning

Conclusion of the Interview

  • Additions, reachability
  • Evaluation of the new information
  • Next steps

Learning to Interrogate

To learn different interview and interrogation techniques, there are several methods and also coaches (particularly in the USA). The Reid Method is quite popular ( but also the training by Don Rabon.

Axel Wendler from Germany (judge at the Higher Regional Court) gives interesting insights regarding a statement’s trustworthiness. 

Of course, interrogations and interviews are a major part of police work. Therefore a lot of information and methods are available for this line of work. The private or corporate investigator does not have quite as many options. Still, both groups have a lot in common and there are experienced detectives who share their knowledge in workshops (ASW Nordrhein-Westfalen is one of the institutions that offer workshops:

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