Conducting interviews in an internal investigation: methods and best practices
In any internal investigation — whether it follows an ethics alert, a suspicion of harassment, or a fraud case — the interview plays a central role. While digital sources (emails, logs, files) and technical means (video surveillance, eDiscovery, forensics) keep multiplying, human testimony remains invaluable. Why? Because it alone allows investigators to understand intent, contextualize the facts, and confront conflicting accounts.
How do you conduct an investigation interview in a structured, impartial, and safe manner? Which tools can support this approach without distorting the human dimension of the exchange?
This article is part of our series dedicated to the six sources of evidence in an internal investigation.
Why the interview remains a fully-fledged source of evidence
An interview is not merely a narrative supplement to "hard" evidence. It is an autonomous source of evidence, with its own legal and operational value.
What the interview provides that other sources cannot
Contextualizing the facts. A suspicious email, an unusual bank transfer, or a system connection at an odd hour is never enough to establish intent or responsibility. The interview allows investigators to reconstruct context: why was this action taken? Who knew about it? What was the decision-making chain?
Confronting accounts. Every stakeholder — the whistleblower, the accused, the witnesses — holds a piece of the truth. The interview makes it possible to collect these narratives, confront them, and identify inconsistencies or points of convergence. This narrative triangulation is indispensable for forming a complete picture.
Identifying new leads. A witness may mention a forgotten document, a colleague who has not yet been interviewed, or an informal practice no one was aware of. The interview opens doors that digital traces alone do not always reveal.
Guaranteeing adversarial debate. Even though it is not mandatory, as indicated by a decision of the French Court of Cassation (Case No. 24-13.234), giving the accused person a voice can prove useful. The interview is the moment when they can present their defense, contest the alleged facts, produce exculpatory evidence, or confirm the elements they are accused of.
How to conduct an investigation interview: method and posture
An investigation interview is not improvised. It rests on rigorous preparation, an active listening posture, and exhaustive traceability.
1. Prepare the interview in advance
Before any interview, the investigator must:
- Define the objectives: what do we expect from this interview? Confirm a fact? Clarify a timeline? Gather a conflicting account?
- Collect the elements already available: emails, reports, previous testimonies. An investigator should never arrive "cold".
- Prepare an interview guide: a flexible framework, organized by theme or chronology, with open-ended questions. It is not a rigid questionnaire, but a mental map to make sure nothing is forgotten.
2. Set the frame from the opening
The first few minutes determine the quality of the exchange. It is advisable to have a preamble template available so that, at the start of each interview, you can remind the interviewee of the following:
- The purpose of the interview without going into the details of the alleged facts (so as not to influence the person being interviewed).
- The importance of confidentiality: specify who will have access to the interview report and how the information will be protected.
- Emphasize neutrality: the investigator is neither judge nor lawyer. They gather facts, not judgments.
- Explain how it will proceed: estimated duration, the possibility of taking breaks, the right to review the report.
3. Use open-ended questioning techniques
The PEACE method (Preparation and Planning, Engage and Explain, Account, Closure, Evaluation), developed in the United Kingdom for judicial investigations, is widely used in professional investigations. Its key principles:
- Open-ended questions: "Can you tell me what happened that day?" rather than "Were you at the meeting?"
- Active listening: allow silences, rephrase to check understanding, do not interrupt.
- Emotional neutrality: never show surprise, approval, or judgment in response to answers.
- Targeted follow-ups: return to a vague point without suggesting the expected answer.
The objective: obtain a free, unconstrained account that reflects the actual perception of the person being interviewed.
4. Ensure the traceability of the interview
An interview with no written record has no evidentiary value. Three imperatives:
- Live note-taking: handwritten or digital, it must be as faithful as possible. Some investigators use a second listener dedicated to this task.
- A structured interview report: written immediately after the interview, it captures the key points, verbatim quotes, and inconsistencies observed.
- Signing the report: it is also useful to offer the interviewee the opportunity to sign the interview report, possibly adding corrections or clarifications. This gesture formalizes agreement on what was said.
Tools at the service of the interview: support, never a substitute
Technology can facilitate the conduct and traceability of interviews — provided it remains a methodological support, never a substitute for human intelligence.
Automatic transcription tools
Dedicated solutions such as Luciole or TL;DV transcribe oral exchanges in real time. They make note-taking easier and allow investigators to return to a specific passage. Limitations: automatic transcription captures neither silences, nor hesitations, nor non-verbal expressions — all essential clues for the investigator.
Case management platforms with an interview module
Some platforms, such as Evidencia, integrate dedicated interview management modules:
- Scheduling of interviews (calendar, automatic invitations);
- Audio recording and transcription;
- Centralized storage of reports within the investigation file;
- Review tracking and electronic signature;
- Timestamping of each step to guarantee procedural traceability.
These platforms offer a coherent overview: the interview is no longer an isolated document, but a building block of a global file, connected to collected emails, digital evidence, and other testimonies.
Secure videoconferencing tools
In a hybrid work context or for multi-site investigations, standard messaging solutions (Teams, Hangouts, etc.) make it possible to conduct remote interviews. Essential precaution: obtain the explicit consent of the person being interviewed before any recording.
Best practices: key takeaways
- Never underestimate preparation: an improvised interview produces incomplete or biased testimonies.
- Systematically document: a signed report protects both the investigator and the interviewee.
- Train investigators: interviewing is a skill that can be learned. Training in the PEACE method or active listening is extremely useful to get the most out of an interview.
- Use technology with discernment: tools facilitate management, but they never replace human judgment, empathy, and critical analysis skills.
The investigation interview is a delicate exercise, at the crossroads of law, psychology, and procedural rigor. Conducted well, it illuminates grey areas, provides solid evidence, and protects everyone's rights. Conducted poorly, it can bias the investigation, weaken conclusions, and expose the organization to legal challenges. In a world where digital data proliferates, human testimony — gathered with method, respect, and traceability — remains one of the pillars of every successful internal investigation.
Looking to structure your internal investigations and centralize interview management in a secure platform? Discover Evidencia and its dedicated internal investigation modules.
