44 Investigation Interview Questions for the Complainant, Subject and Witnesses

Take your investigation interviews beyond the who, what, where, when, why and how of what happened.

Posted by Dawn Lomer in on February 9th, 2017

Knowing what questions to ask in an investigation interview comes with experience. Investigators who have interviewed thousands of complainants, witnesses and subjects know the standard questions they should always ask, but they also know the importance of following the trail to ask new questions based on the information revealed. So, while the investigation interview questions below provide a great basis for starting the conversation and covering the basics of what happened, don’t limit yourself. It’s by asking the probing questions that arise from what’s revealed in the conversation that the whole truth is uncovered.

Learn how to use the list of questions in this article as part of your overall investigation interview strategy. Download the free eBook: Investigation Interview Techniques.

Questioning the Complainant

Another reason to take complaints seriously is to assure the complainant and others that the company will follow up and provide a fair assessment of their concerns, no matter how small.
It’s important to take the reporter’s complaint seriously, no matter how frivolous it may seem at first glance. There have been cases of reports of minor infractions that, under investigation, revealed much larger issues.

Another reason to take complaints seriously is to assure the complainant and others that the company will follow up and provide a fair assessment of their concerns, no matter how small. This helps to establish a speak-up culture and increases the chances that people will come forward in the future. The complainant is usually the first person interviewed in an investigation.

Here are 16 sample investigation interview questions to ask the complainant:

  1. What happened?
  2. What was the date, time and duration of the incident or behavior?
  3. How many times did this happen?
  4. Where did it happen?
  5. How did it happen?
  6. Did anyone else see it happen? Who? What did they say? What did they do?
  7. Was there physical contact? Describe it. Demonstrate it.
  8. What did you do in response to the incident or behavior?
  9. What did you say in response to the incident or behavior?
  10. How did the subject of the allegation react to your response?
  11. Did you report this to anyone in management? To whom? When? What they say and/or do?
  12. Did you tell anyone about the incident or behavior? Who? What did they say and/or do?
  13. Do you know whether the subject of the allegation has been involved in any other incidents?
  14. Do you know why the incident or behavior occurred?
  15. Do you know anyone else who can shed light on this incident?
  16. Is there anything else you want to tell me that I haven’t asked you?

Learn more about questioning the complainant. Download the free cheat sheet: 8 Tips for Interviewing the Reporter.


Unposed group of creative business people in an open concept

Questioning Witnesses

Witnesses can help to corroborate or refute the reporter’s account of what happened and shed light on some of the details that the reporter may not have been able or willing to furnish.
After questioning the person who filed the complaint, the next step is to interview any witnesses to the incident being reported. Witnesses can help to corroborate or refute the reporter’s account of what happened and shed light on some of the details that the reporter may not have been able or willing to furnish.

The most compelling witnesses are, of course, those who actually witnessed the incident. But witnesses can also be those who heard about the incident from others who witnessed it or those to whom the reporter relayed the incident after the fact. It can also be helpful to interview witnesses to other incidents that the subject of the complaint was involved in.

These 14 sample investigation interview questions can help get witnesses to talk:

  1. What did you witness?
  2. What was the date, time and duration of the incident or behavior you witnessed?
  3. Where did it happen?
  4. Who was involved?
  5. What did each person do and say?
  6. Did anyone else see it happen? Who?
  7. What did you do after witnessing the incident or behavior?
  8. Did you say anything to the parties involved in response to what you witnessed?
  9. How did the complainant and the subject of the allegation react to your response?
  10. Did you report this to anyone in management? To whom? When? What they say and/or do?
  11. Did you tell anyone about the incident or behavior? Who?
  12. Do you know why the incident or behavior occurred?
  13. Do you know anyone else who can shed light on this incident?
  14. Is there anything else you want to tell me that I haven’t asked you?
Unposed group of creative business people in an open concept

Questioning the “Accused” or Subject of the Complaint

You’ve heard the accounts of everyone else involved in the incident, and it’s difficult to avoid forming an opinion before getting to this crucial interview.
Keeping in mind that the purpose of interviewing the subject of the complaint (also known as the accused) is simply to find out the truth, it’s important to pay attention to credibility clues and be aware of any biases that may affect your judgment. Questioning the accused person is often the most sensitive of all the interviews you will conduct. You’ve heard the accounts of everyone else involved in the incident, and it’s difficult to avoid forming an opinion before getting to this crucial interview. But it’s important that you keep an open mind to avoid making assumptions based on what you’ve already heard.

Here’s what to ask the subject of the complaint:

  1. What happened?

If the subject denies that the incident occurred, ask:

  1. Is there any reason anyone would invent or lie about the incident?
  2. Where were you when the alleged incident occurred?
  3. Do you have any witnesses who can corroborate your whereabouts at the time of the incident?

If the subject doesn’t deny that the incident occurred, ask:

  1. When and where did this happen?
  2. What were the circumstances leading up to the incident?
  3. Who else was involved?
  4. What is your connection to the complainant?
  5. Are you aware of any other complaints by this person?
  6. Recount the dialogue that occurred in order of what was said.
  7. What did the complainant do or say?
  8. Is there any evidence to support your account of what happened?
  9. Is there anyone else we should talk to who had knowledge of the incident or the circumstances surrounding it?
  10. Have you talked to anyone about the incident? Who? What did you tell them?

You’ll “catch more flies with honey”. Learn how to get interview subjects to talk to you by downloading the free cheat sheet on Building Rapport.

Tips for Questioning All Parties in an Investigation

Everyone has personal biases and it’s an investigator’s job to recognize those biases and take them into account.
The most important thing to remember when conducting investigation interviews is that your main objective is to simply find out the truth about what happened. There will be barriers, detours and challenges along the way, but as long as you stay focused on that one goal, you’ll stay on track.

One of the challenges you’ll face is staying objective. Everyone has personal biases and it’s an investigator’s job to recognize those biases and take them into account. This takes a great deal of self-awareness and self-control, but an excellent investigator has both of these qualities.

When assessing the creditability of the subject, complainant and witnesses, you’ll also need to keep your biases in check and follow best practices. Before beginning the questioning phase above, ask some basic questions that are not connected with the incident being investigated. They should be non-threatening questions to which you already know the answers. This helps you to establish a baseline against which you can measure the person’s subsequent behavior, language and manner.

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Baseline Questions

Examples of baseline questions are:

  • How long have you worked at the company?
  • What is your position?
  • How long have you been in this position?

Notice the interviewee’s speech patterns, gestures and degree of eye contact when answering these non-threatening questions. This helps you to assess whether there are differences in their behavior when you ask questions related to the incident.

For more information on what to listen for when assessing credibility, download the free cheat sheet on Detecting Deception in Investigation Interviews.

Ending the Interview

Once they aren’t being questioned, interview subjects have been known to divulge revealing details that weren’t discussed during the interview.
Sometimes that last few minutes in the interviewing room can be the most productive phase of the interview. Thank the interviewee for their time and for helping you to get to the truth. Pack up slowly and allow silence to hang in the air to give the person an opportunity to be forthcoming with more information.

Once they aren’t being questioned, interview subjects have been known to divulge revealing details that weren’t discussed during the interview. Investigators shouldn’t discount this important opportunity to hear what they have to add.

Whether or not your subject is more forthcoming at the end of the interview, it’s important to end the session on a positive note by thanking them for their help and providing your contact information in case they think of something they would like to add. If they leave feeling positive about the experience and you, they are more likely to help you in the future.

Dawn Lomer
Dawn Lomer

Managing Editor

Dawn Lomer is the managing editor at i-Sight Software and a Certified Fraud Examiner (CFE). She writes about topics related to workplace investigations, ethics and compliance, data security and e-discovery, and hosts i-Sight webinars.