Police Skills Police Test Study Guide

How to Interview a Suspect.

May 7th, 2021
how to interview a suspect

Interviewing Suspects Effectively

Interviewing suspects is one of the most important skills that police officers must develop. It’s not something that you can learn overnight, but it is something that you can develop with experience.

Knowing how to interview a suspect is incredibly valuable.

In time, it will become almost instinctual. You will develop a kind of nous where you realize something isn’t quite right. The facts do not add up, or perhaps the suspect is behaving suspiciously.

To detect when suspects are lying, it involves a combination of three factors:

  • Effective and targeted interview technique / questioning
  • Evidence
  • How the suspect behaves / their body language

No one factor is sufficient, though all three – when combined – produce the most effective result.

Body language is one of the most misunderstood and misapplied aspects of detecting lies. Below, we learn more about how to distinguish between the body language that matters versus the popular alternatives that do not provide much by way of evidence.

Body Language and Detecting Truth

Popular body language techniques are next to useless to establish whether a suspect is lying. That’s not to say that body language analysis is all bad, but that popular notions of what body language means is often erroneous.

Examples include:

  • If someone moves their eyes to the upper left/right corner, it means they are lying.
  • If someone folds their arms, it means they are trying to hide something.

Nobody can establish whether someone is telling the truth based on popular myths and notions such as this. Furthermore, it takes from the real information you must take from an interrogation or police officer interview.

That’s not to say body language has no role in how to interview a suspect, but it must be used as one tool within a broader arsenal of weapons.

Case Study: Drug Smuggling

As we have learned, interpreting body language is not all bad.

Police officers must put body language into a broader context. Immigration officers routinely use body language techniques to establish whether a visitor has something to hide. But this is more bodily reaction than body language. For instance, drug smugglers coming from South America offer the context – namely, that drug smugglers are more likely to be sourced from these routes.

Passengers who look noticeably nervous, and who happen to be sweating a lot, may have something to hide. This sweating is even more common in passengers who have recently taken an illicit drug. Immigration officers are aware of this and have devised a range of effective tests to identify illegal drugs. Passengers who have recently taken an illicit drug will sweat metabolites of the drug through their feet into their shoes. A rapid swab test of the shoes can then identify an illicit drug in seconds and, if so, further investigation will be performed to establish whether the passenger has illegally smuggled drugs into the country. Full body scans can be performed to learn whether the passenger has swallowed any packets.

But ultimately what led to this case was body language alone – and how the passenger reacts to the environment they find themselves. In other words, there is a broader context to consider, and this is where body language fits in, and not the other way around. Body language must only be used as one tool in a much broader arsenal. Aside from this, there are other interrogative techniques that police officers can deploy to learn how to tell suspects are lying.

Consistent Stories

All candidates vying to become law enforcement officers must take the oral board exam – one core part of the police test. During this test, you will be asked a series of questions and interrogated as such. Many of the core techniques that the oral board panel use can also be applied to real-life interrogations.

When interviewing any suspect, it is important to establish that stories are consistent. Let’s consider a further airport example: a husband and wife who arrive with more cigarettes than they are permitted to carry. If they are found to be carrying far more than the mandated limits, both suspects will be interviewed separately – and asked the same range of questions. There must be a broad range of questions – both broad and specific. Suspects must be confident with their answers and both stories must add up. Of course, it is conceivable that both suspects pre-arranged a story. In these cases, more tangential questions can be asked that the suspects are highly unlikely to have considered.

This technique also applies to many other aspects of law enforcement – whether it is patrolling the streets and interviewing both sides of an argument, or whether its interviewing a suspected murderer and his family and/or alibis.

Be Friendly

Always strive to be on good terms with the suspect.

The more amiable that officers are to suspects, the more likely that suspects will open-up or cooperate to a greater degree than they otherwise would have. Needlessly aggravating the suspect may only serve to close them up, become angry and self-isolated in their ability to cooperate with the investigation.

It’s also a good idea to ask suspects their opinions. Opinions are more open-ended questions and, if the officer appears to be on good terms with the suspect, he/she may reveal more information about themselves than they otherwise would have.

You would be surprised just how much information you can gain not only from opinions uttered during the interview, but also in the pre- and post-interview phase, too. The questions may be formal or informal, and may even be humorous to some degree, but the primary purpose remains the same: to extract detail and context from the suspect, details they may later forget they have given.

This can extract the information you need to tell when the suspect is lying.

Ask the Right Questions

There are four kinds of question police officers can deploy:

  • Closed-ended questions: “Who did…?”, “Did you…?”.
  • Open-ended questions: “Explain how…?”, “What happened…?”.
  • Funnel questions: “When did you leave the office?”.
  • Analytical questions: “Why would someone do something like that?”.

Funnel questions are valuable because you should already know the answer to these questions. But even if you do not know, the technique is still highly effective. The purpose of the funnel question is, like a funnel, to start with a broad question, and then slowly ask more specific and specific questions until you get to the detail you need.

Furthermore, police officers often start from the opposite perspective. They may pretend to have the information when in fact they do not. For example, an officer could approach a suspect and say, “You were in the office at 7.10pm last night, correct?”. There are many formulations but what matters is that the interview takes a logical, structured approach where information is gleaned from suspects in the most effective manner possible.

Some officers create the impression that they have all the information they need prior to the interview and that all the suspect must do is confirm this information. Props, such as folders and files, can be placed on the table to create the impression that this information is now readily accessible to officers. Suspects are not told about these files and folders, but they are merely placed on the table for psychological reasons alone.

Take Home Message

As prospective police officers, it is important to learn investigative and interrogative techniques – how to properly conduct an interview and how to tell when suspects are lying. These techniques will be with you for your entire career as a law enforcement officer.

Here, we have put together the top techniques used for how to interview a suspect. Of course, the precise techniques used differs from officer to officer.

You too will develop your own style and technique.

But what weaves together all styles is the ability to ask the right question, extract the evidence required, and to develop a sense of when things aren’t quite right.

As long as that remains your focus, you will no doubt develop these skills in time.

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